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Appropriate biomarkers are required to predict the clinical outcome of triple-negative breast cancer (TNBC). In this study, we focused on the clinical importance of two representative tumor-associated proteins, Bcl-2 and p53. Bcl-2 expression is usually related to estrogen receptor expression and a favorable outcome in breast cancer. TNBC has been reported to show a high frequency of p53 positivity suggesting TP53 mutations. The expressions of Bcl-2 and p53 were immunohistochemically examined in TNBC involving two age groups of postmenopausal women (≥75 y/o, n = 75; 55-64 y/o, n = 47), who underwent surgery without neoadjuvant therapy. We examined their associations with each other, or with clinicopathological factors including the outcome. Bcl-2 expression was inversely correlated with androgen receptor, apocrine morphology, and p53 expressions, and was an independent predictor of a poor outcome in total or in younger women. p53 positivity was associated with a more favorable outcome than p53 negativity in the younger group. In combined analyzes, none of the twenty Bcl-2-negative/p53-positive cases in the younger group exhibited recurrence, resulting in the independent favorable predictive value of Bcl-2-negative/p53-positive. The anti-apoptotic nature of Bcl-2 may be apparent in TNBC. The excellent outcome of Bcl-2-negative/p53-positive cases in the younger group warrants further combined investigation of Bcl-2/p53 in TNBC., (© 2024 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.)

Overexpression of antibody light chains in small plasma cell clones can lead to misfolding and aggregation. On the other hand, the formation of amyloid fibrils from antibody light chains is related to amyloidosis. Although aggregation of antibody light chain is an important issue, atomic-level structural examinations of antibody light chain aggregates are sparse. In this study, we present an antibody light chain that maintains an equilibrium between its monomeric and tetrameric states. According to data from X-ray crystallography, thermodynamic and kinetic measurements, as well as theoretical studies, this antibody light chain engages in 3D domain swapping within its variable region. Here, a pair of domain-swapped dimers creates a tetramer through hydrophobic interactions, facilitating the revelation of the domain-swapped structure. The negative cotton effect linked to the β-sheet structure, observed around 215 nm in the circular dichroism (CD) spectrum of the tetrameric variable region, is more pronounced than that of the monomer. This suggests that the monomer contains less β-sheet structures and exhibits greater flexibility than the tetramer in solution. These findings not only clarify the domain-swapped structure of the antibody light chain but also contribute to controlling antibody quality and advancing the development of future molecular recognition agents and drugs., (© 2023. The Author(s).)

Formate dehydrogenases (FDHs) catalyze the two-electron oxidation of formate to carbon dioxide. FDHs can be divided into several groups depending on their subunit composition and active-site metal ions. Metal-dependent (Mo- or W-containing) FDHs from prokaryotic organisms belong to the superfamily of molybdenum enzymes and are members of the dimethylsulfoxide reductase family. In this short review, recent progress in the structural analysis of FDHs together with their potential biotechnological applications are summarized., (open access.)

[NiFe]-hydrogenase from Desulfovibrio vulgaris Miyazaki F is an O 2 -sensitive enzyme that is inactivated in the presence of O 2 but the oxidized enzyme can recover its catalytic activity by reacting with H 2 under anaerobic conditions. Here, we report the first neutron structure of [NiFe]-hydrogenase in its oxidized state, determined at a resolution of 2.20 Å. This resolution allowed us to reinvestigate the structure of the oxidized active site and to observe the positions of protons in several short hydrogen bonds. X-ray anomalous scattering data revealed that a part of the Ni ion is dissociated from the active site Ni-Fe complex and forms a new square-planar Ni complex, accompanied by rearrangement of the coordinated thiolate ligands. One of the thiolate Sγ atoms is oxidized to a sulfenate anion but remains attached to the Ni ion, which was evaluated by quantum chemical calculations. These results suggest that the square-planar complex can be generated by the attack of reactive oxygen species derived from O 2 , as distinct from one-electron oxidation leading to a conventional oxidized form of the Ni-Fe complex. Another major finding of this neutron structure analysis is that the Cys17 S thiolate Sγ atom coordinating to the proximal Fe-S cluster forms an unusual hydrogen bond with the main-chain amide N atom of Gly19 S with a distance of 3.25 Å, where the amide proton appears to be delocalized between the donor and acceptor atoms. This observation provides insight into the contribution of the coordinated thiolate ligands to the redox reaction of the Fe-S cluster., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

[FeFe] hydrogenases are exceptionally active catalysts for the interconversion of molecular hydrogen with protons and electrons. Their active site, the H-cluster, is composed of a [4Fe-4S] cluster covalently linked to a unique [2Fe] subcluster. These enzymes have been extensively studied to understand how the protein environment tunes the properties of the Fe ions for efficient catalysis. The sensory [FeFe] hydrogenase (HydS) from Thermotoga maritima has low activity and displays a very positive redox potential for the [2Fe] subcluster compared to that of the highly active prototypical enzymes. Using site directed mutagenesis, we investigate how second coordination sphere interactions of the protein environment with the H-cluster in HydS influence the catalytic, spectroscopic and redox properties of the H-cluster. In particular, mutation of the non-conserved serine 267, situated between the [4Fe-4S] and [2Fe] subclusters, to methionine (conserved in prototypical catalytic enzymes) gave a dramatic decrease in activity. Infra-red (IR) spectroelectrochemistry revealed a 50 mV lower redox potential for the [4Fe-4S] subcluster in the S267M variant. We speculate that this serine forms a hydrogen bond to the [4Fe-4S] subcluster, increasing its redox potential. These results demonstrate the importance of the secondary coordination sphere in tuning the catalytic properties of the H-cluster in [FeFe] hydrogenases and reveal a particularly important role for amino acids interacting with the [4Fe-4S] subcluster., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Electron bifurcation is a fundamental energy conservation mechanism in nature in which two electrons from an intermediate-potential electron donor are split so that one is sent along a high-potential pathway to a high-potential acceptor and the other is sent along a low-potential pathway to a low-potential acceptor. This process allows endergonic reactions to be driven by exergonic ones and is an alternative, less recognized, mechanism of energy coupling to the well-known chemiosmotic principle. The electron-bifurcating [FeFe] hydrogenase from Thermotoga maritima (HydABC) requires both NADH and ferredoxin to reduce protons generating hydrogen. The mechanism of electron bifurcation in HydABC remains enigmatic in spite of intense research efforts over the last few years. Structural information may provide the basis for a better understanding of spectroscopic and functional information. Here, we present a 2.3 Å electron cryo-microscopy structure of HydABC. The structure shows a heterododecamer composed of two independent 'halves' each made of two strongly interacting HydABC heterotrimers connected via a [4Fe-4S] cluster. A central electron transfer pathway connects the active sites for NADH oxidation and for proton reduction. We identified two conformations of a flexible iron-sulfur cluster domain: a 'closed bridge' and an 'open bridge' conformation, where a Zn 2+ site may act as a 'hinge' allowing domain movement. Based on these structural revelations, we propose a possible mechanism of electron bifurcation in HydABC where the flavin mononucleotide serves a dual role as both the electron bifurcation center and as the NAD + reduction/NADH oxidation site., Competing Interests: CF, NC, PG, WL, HO, JB, JB No competing interests declared, (© 2022, Furlan, Chongdar et al.)

Gases like H 2 , N 2 , CO 2 , and CO are increasingly recognized as critical feedstock in "green" energy conversion and as sources of nitrogen and carbon for the agricultural and chemical sectors. However, the industrial transformation of N 2 , CO 2 , and CO and the production of H 2 require significant energy input, which renders processes like steam reforming and the Haber-Bosch reaction economically and environmentally unviable. Nature, on the other hand, performs similar tasks efficiently at ambient temperature and pressure, exploiting gas-processing metalloenzymes (GPMs) that bind low-valent metal cofactors based on iron, nickel, molybdenum, tungsten, and sulfur. Such systems are studied to understand the biocatalytic principles of gas conversion including N 2 fixation by nitrogenase and H 2 production by hydrogenase as well as CO 2 and CO conversion by formate dehydrogenase, carbon monoxide dehydrogenase, and nitrogenase. In this review, we emphasize the importance of the cofactor/protein interface, discussing how second and outer coordination sphere effects determine, modulate, and optimize the catalytic activity of GPMs. These may comprise ionic interactions in the second coordination sphere that shape the electron density distribution across the cofactor, hydrogen bonding changes, and allosteric effects. In the outer coordination sphere, proton transfer and electron transfer are discussed, alongside the role of hydrophobic substrate channels and protein structural changes. Combining the information gained from structural biology, enzyme kinetics, and various spectroscopic techniques, we aim toward a comprehensive understanding of catalysis beyond the first coordination sphere.

The sensitivity and specificity of a new automated electrochemiluminescence immunoassay system, Elecsys ® Anti-p53 (Elecsys), were compared with that of the conventional serum anti-p53 antibody (s-p53-Ab) enzyme-linked immunosorbent assay kit [MESACUP anti-p53 test (MESACUP)]. Elecsys and MESACUP were used to analyze the levels of s-p53-Abs in patients with esophageal, colorectal and breast cancer. A total of 532 controls and 288, 235 and 329 patients with esophageal, colorectal and breast cancer, respectively, were enrolled. Additionally, the sera of patients with benign diseases of the esophagus, colorectal system and breast, patients with autoimmune diseases and healthy volunteers were analyzed as controls. Sensitivity and specificity were compared between the two assay systems. Positive agreement rates were 58.7% in all samples, 71.2% in esophageal samples, 73.6% in colorectal samples and 35.1% in breast samples. Negative agreement rates for the different cancer types were ≥97.1% and the overall agreement rates were ≥92.3%. When the specificities of the two assays were aligned for all samples, Elecsys demonstrated higher sensitivities for all types of analyzed cancer together, as well as for esophageal, colorectal and breast cancer, respectively. Although positive concordance between the two assay systems was low in terms of specificity, Elecsys had a higher sensitivity than the MESACUP., Competing Interests: HSh received research funding from Ono Pharmaceutical, Taiho Pharmaceutical and Roche Diagnostics K.K. HSu was an employee of Roche Diagnostics K.K. ME is an employee of Roche Diagnostics GmbH. The Elecsys assay system is manufactured by Roche Diagnostics K. K., (Copyright: © Suzuki et al.)

Hydrogenases catalyze the reversible oxidation of H 2 . Carbon monoxide (CO) is known to be a competitive inhibitor of O 2 -sensitive [NiFe]-hydrogenases. Although the activities of some O 2 -tolerant [NiFe]-hydrogenases are unaffected by CO, the partially O 2 -tolerant [NiFe]-hydrogenase from Citrobacter sp. S-77 (S77-HYB) is inhibited by CO. In this work, the CO-bound state of S77-HYB was characterized by activity assays, spectroscopic techniques and X-ray crystallography. Electron paramagnetic resonance spectroscopy showed a diamagnetic Ni 2+ state, and Fourier-transform infrared spectroscopy revealed the stretching vibration of the exogenous CO ligand. The crystal structure determined at 1.77 Å resolution revealed that CO binds weakly to the nickel ion in the Ni-Fe active site of S77-HYB. These results suggest a positive correlation between O 2 and CO tolerance in [NiFe]-hydrogenases.

Aims: L-type amino acid transporter 1 (LAT1) is a major Na + -independent neutral amino acid transporter, forming a complex with CD98hc. The aim of this study is to investigate the significance of LAT1 and CD98hc in invasive breast cancer., Methods: LAT1 and CD98hc expression was immunohistochemically assessed in 280 invasive breast cancers and analysed for association with clinicopathological features., Results: High levels of LAT1 and CD98hc were observed in triple-negative breast cancers (TNBCs) possessing negative immunoreactivity with oestrogen receptor, progesterone receptor and human epidermal growth factor receptor 2, compared with non-TNBCs (NTNBCs), and were associated with lymph-node metastasis and higher nuclear grade. The high-LAT1-expression group showed a poor prognosis in NTNBC and TNBC, however, high-CD98hc-expression group showed a poor prognosis only in NTNBC. LAT1 and CD98hc expression could be the prognostic factors in univariate analyses, but not in multivariate analyses. Further, we found that invasive tumour components showed higher LAT1 and CD98hc expression than non-invasive tumour components., Conclusions: LAT1 and CD98hc may possess prognostic values in invasive breast cancer. LAT1 may be linked with cancer cell activities and disease progression in breast cancer., Competing Interests: Competing interests: HE is the Chief Executive Officer (CEO) and KH is an employee of J-Pharma, and both participated in this study with technical assistance., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: We hypothesized that innate immune response pathways might be involved in thyroid carcinogenesis. To investigate this hypothesis, we aimed at analyzing the expression of several receptors and molecules in the innate immune system in papillary thyroid carcinoma (PTC) and anaplastic thyroid carcinoma (ATC) tissues., Methods: Of the surgically resected specimens, 11 ATC tissues, 25 PTC tissues, and 8 nodular hyperplasia (NH) tissues were selected and examined for the expression of toll-like receptor (TLR) 2, TLR3, TLR4, TLR5, TLR7, TLR9, the myeloid differentiation primary response gene 88 (MyD88), and toll-interleukin-1 receptor domain-containing adaptor inducing INF- β (TRIF) by immunohistochemistry (IHC)., Results: Several TLRs were expressed in each tissue. TLR3 was strongly expressed in all tissues. In contrast, TLR4 was not detected in any tissues. While TLR5 was moderately expressed in NH but significantly reduced in PTC and ATC, TLR9 was absent in NH tissue but moderately expressed in both PTC and ATC. On MyD88 expression, no significant difference was found between PTC and ATC. TRIF was significantly upregulated in PTC and ATC compared to NH. Surprisingly, PTC and ATC tissues exhibited similar expression patterns of TLRs, MyD88, and TRIF., Conclusion: These data suggest the involvement of the innate immune system in both PTC and ATC. Specifically, TLR3-mediated TRIF activation was confirmed in PTC and ATC. This provides new insight into thyroid carcinogenesis., Competing Interests: The authors declare that they have no conflicts of interest regarding the publication of this article., (Copyright © 2021 Yasuhiro Nihon-Yanagi et al.)

Because the production of tumor-associated antibodies (TAA) is a humoral immune response in cancer patients, serum autoantibodies may be detected even in patients with early-stage tumors. Seventeen recombinant proteins with tags in Escherichia coli (p53, RalA, p90, NY-ESO-1, HSP70, c-myc, galectin-1, Sui1, KN-HN-1, HSP40, PrxVI, p62, cyclin B1, HCC-22-5, annexin II, HCA25a, and HER2) were applied as capturing antigens in sandwich ELISA to measure serum IgG levels. Sera from 73 healthy donors and 386 patients with breast cancer, including 182 stage 0/I patients, were evaluated using cutoff values for each TAA equal to the mean +3 SD of the serum levels of healthy controls. The positive TAA rates were relatively high for p53 (10%) and RalA (10%). The positive rates of all TAA of stage 0/I were similar to those of all patients. Even in the stage 0/I patients, 24% showed that two or more TAA were positive, and the positive rate of a five-TAA combination assay was 37%. The positivity rate was significantly higher for the non-luminal type than for the luminal type (P = .003). Logistic analysis showed that seropositivity (positive for one or more TAA) in breast cancer patients was independent from any TNM factor or disease stage and was significantly associated with histological grade in the multivariate analysis (P = .007). TAA in breast cancer patients may be useful for early detection. However, seropositivity of breast cancer reflects the tumor characteristics but not the disease stage., (© 2021 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Triple-negative breast cancer (TNBC) lacks an effective treatment target and is usually treated with chemotherapy. Treatment of older patients with TNBC, however, should be decided carefully because of the side effects of chemotherapy in this population. Some forms of TNBC are associated with a favorable prognosis and do not require chemotherapy. To optimize the treatment of older patients with TNBC, it is important to know the clinicopathological characteristics and a prognostic marker. In this study, classic clinicopathological factors, immunohistochemical characteristics (androgen receptor [AR], cytokeratin 5/6 [CK5/6], epidermal growth factor receptor), tumor-infiltrating lymphocytes (TILs), and the clinical outcome based on the status of each biomarker were compared among a consecutive series of female patients with TNBC aged ≥75 years (n = 75) and among those aged 55-64 years matched for the pathological stage (n = 47) who underwent surgery without neoadjuvant therapy. TNBC with special histology (particularly apocrine carcinoma, pleomorphic invasive lobular carcinoma, and metaplastic carcinoma) was more frequent in the older group than in the younger group (35/75, 57% versus 11/47, 23%, P = 0.010). The AR positivity rate was higher in older patients than in younger patients, whereas TILs and CK5/6 exhibited the opposite results. In multivariate analyses, AR positivity was an independent predictor of a favorable outcome in older patients (lower recurrence rate), whereas the high level of TILs was favorable in younger patients (lower recurrence and mortality rates). AR positivity or apocrine morphology was frequent and predicts a favorable clinical outcome in older patients with TNBC, suggesting the importance of AR examination in this population., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: We examined the vascularity of mammary Paget disease histologically to confirm the increased blood flow observed previously by clinical imaging. The relationships among blood vessel density (BVD), histopathological parameters of blood flow in the nipple, and the expression of angiogenic factors such as basic fibroblast growth factor (bFGF) and vascular endothelial growth factor A (VEGFA) were examined., Methods: We calculated the average CD34-positive BVD and podoplanin (D2-40)-positive lymphatic vessel density (LVD) and the proportion of proliferating of endothelial cells in 14 Paget disease, 3 dermatitis biopsy, and 14 age-matched control cases. As a parameter related to blood flow in the nipple, the total CD34-positive blood vessel lumen area relative to the entire nipple area was measured in each Paget disease and control case using an automated image analysis system. Immunohistochemical expression of bFGF and VEGFA in Paget cells was also examined., Results: The average BVD and LVD were significantly higher in the Paget disease cases than in the dermatitis (p = 0.003) and control (p < 0.001) cases. The proportion of proliferating endothelial cells was also increased in the Paget disease cases. The ratio of the CD34-positive blood vessel lumen area to nipple area was also significantly higher in the Paget disease than control cases (p = 0.003). The average BVD was correlated with the average LVD (r = 0.734, p < 0.001) and ratio of the blood vessel lumen area to nipple area (r = 0.692, p < 0.001). Immunohistochemical expression of bFGF was strong in all Paget disease cases, with a significantly higher expression score in the Paget disease than dermatitis (p = 0.003) and control (p < 0.001) cases. The bFGF, but not VEGFA, expression score, was strongly correlated with the average BVD (r = 0.818, p < 0.001) and ratio of the blood vessel lumen area to nipple area (r = 0.503, p = 0.006)., Conclusion: These results provide direct histopathological evidence of a marked increase in nipple blood flow in Paget disease detected by clinical imaging. bFGF is considered to play a pivotal role in angiogenesis in mammary Paget disease.

BACKGROUND Dermatomyositis (DM) is occasionally associated with malignancy, which is so-called cancer-associated myositis. The cancer screening in patients with dermatomyositis is an important clinical issue. That is because malignant disease underlying dermatomyositis is potentially life-threatening. Transcriptional intermediary factor 1γ (TIF1γ) antibodies (anti-TIF1γ Abs) are one of the myositis-specific autoantibodies, which are investigated as potential predictors of malignancy in patients with dermatomyositis. However, the etiology of anti-TIF1γ Abs generations in various cancer patients is not known. CASE REPORT A 70-year-old male patient was admitted for muscle pain and weakness in both legs. Erythematous on the face, eruption, and a V sign were also observed. Laboratory tests showed the elevation of creatine kinase, myoglobin, and aldolase. He was diagnosed as dermatomyositis. Cancer screening was performed, and esophageal cancer was detected in the lower esophagus. Despite the symptoms of dermatomyositis were improved with steroid, methotrexate, and radical esophagectomy, he died with esophageal cancer 3 years after the onset of dermatomyositis. TIF1γ is frequently overexpressed in cancer tissues. Therefore, some cancer patients without dermatomyositis could be positive for anti-TIF1γ Abs. We retrospectively analyzed anti-TIF1γ Abs in cancer patients (n=131). However, the screening of anti-TIF1γ Abs in cancer patients without dermatomyositis (n=130) showed there were no seropositive patients. Only this cancer-associated myositis patient was positive for anti-TIF1γ Abs. CONCLUSIONS Our result suggested the generation of anti-TIF1γ Abs is specific for cancer associated myositis, not for tumorigenesis.

The heterotrimeric electron-bifurcating [FeFe] hydrogenase (HydABC) from Thermotoga maritima (Tm) couples the endergonic reduction of protons (H + ) by dihydronicotinamide adenine dinucleotide (NADH) (∆G 0  ≈ 18 kJ mol -1 ) to the exergonic reduction of H + by reduced ferredoxin (Fd red ) (∆G 0  ≈ - 16 kJ mol -1 ). The specific mechanism by which HydABC functions is not understood. In the current study, we describe the biochemical and spectroscopic characterization of TmHydABC recombinantly produced in Escherichia coli and artificially maturated with a synthetic diiron cofactor. We found that TmHydABC catalyzed the hydrogen (H 2 )-dependent reduction of nicotinamide adenine dinucleotide (NAD + ) in the presence of oxidized ferredoxin (Fd ox ) at a rate of  ≈17 μmol NADH min -1  mg -1 . Our data suggest that only one flavin is present in the enzyme and is not likely to be the site of electron bifurcation. FTIR and EPR spectroscopy, as well as FTIR spectroelectrochemistry, demonstrated that the active site for H 2 conversion, the H-cluster, in TmHydABC behaves essentially the same as in prototypical [FeFe] hydrogenases, and is most likely also not the site of electron bifurcation. The implications of these results are discussed with respect to the current hypotheses on the electron bifurcation mechanism of [FeFe] hydrogenases. Overall, the results provide insight into the electron-bifurcating mechanism and present a well-defined system for further investigations of this fascinating class of [FeFe] hydrogenases.

Purpose: To clarify the profile of adverse events from endocrine therapies in older patients., Methods: We surveyed 15 subjective symptoms including hot flashes, sweating, knuckle stiffness, knee/shoulder joint pain, limb numbness, lethargy, forgetfulness, depressive state, irritated state, genital bleeding, leukorrhea increase, vaginal dryness, bone fracture, and weight gain by a questionnaire among 2044 patients over 55 years old (total number of answered sheets, 8875) and compared the results according to age (56-69 years old vs. ≥ 70 years old) and type of therapy (aromatase inhibitors (AIs) vs. selective estrogen receptor modulators (SERMs)). Among patients 56-69 years old, 6093 and 314 responses were from patients treated with AIs (1477 patients) and SERMs (123 patients), respectively, and 2292 and 176 responses were from those ≥ 70 years old treated with AIs (581 patients) and SERMs (51 patients), respectively., Results: In patients ≥ 70 years old, sweating, knuckle stiffness, knee/shoulder joint pain, limb numbness, and lethargy were significantly more frequent/severe with AIs than with SERMs. In those aged 56-69, knuckle stiffness and vaginal dryness were significantly more frequent with AIs than with SERMs, but the opposite occurred for hot flashes, leukorrhea increase, genital bleeding, and weight gain., Conclusions: Among patients ≥ 70 years old, many symptoms were significantly more frequent/severe with AIs than with SERMs, compared with those aged 56-69, which suggests a difference in the profile of adverse events according to the type of endocrine therapy and the patient's age. It is important to consider the benefits and risks of each treatment to optimize endocrine therapy for older patients.

Sulfur isotope fractionation resulting from microbial sulfate reduction (MSR) provides some of the earliest evidence of life, and secular variations in fractionation values reflect changes in biogeochemical cycles. Here we determine the sulfur isotope effect of the enzyme adenosine phosphosulfate reductase (Apr), which is present in all known organisms conducting MSR and catalyzes the first reductive step in the pathway and reinterpret the sedimentary sulfur isotope record over geological time. Small fractionations may be attributed to low sulfate concentrations and/or high respiration rates, whereas fractionations greater than that of Apr require a low chemical potential at that metabolic step. Since Archean sediments lack fractionation exceeding the Apr value of 20‰, they are indicative of sulfate reducers having had access to ample electron donors to drive their metabolisms. Large fractionations in post-Archean sediments are congruent with a decline of favorable electron donors as aerobic and other high potential metabolic competitors evolved.

Introduction: Triple-negative breast cancer (TNBC), which lacks expression of estrogen receptor (ER), progesterone receptor (PgR), and epidermal growth factor receptor 2 (HER2), currently has no effective hormonal or molecular target therapy., Objective and Methods: To elucidate the role of the mammalian target of rapamycin (mTOR) signaling pathway in TNBC, the expression of molecules involved in mTOR signaling including mTOR, phosphorylated (p)-mTOR, p-4EBP1, GLUT1, GLUT3, HIF-1α, and Ki67 was investigated by immunohistochemistry in 35 TNBC and 81 non-TNBC cases., Results: Expression of p-mTOR, the activated form of mTOR, but not unphosphorylated mTOR, was significantly higher in non-TNBC cases than in TNBC cases. Expression of p-4EBP1, GLUT1, and GLUT3 was higher in TNBC cases than in non-TNBC cases. When the localization of p-mTOR was classified as nuclear, perinuclear, or cytoplasmic, nuclear localization of p-mTOR was observed more frequently in TNBC than in non-TNBC cases and was correlated with the expression of GLUT1 and GLUT3, which was related to proliferation activity examined with Ki67., Conclusions: mTOR signaling regulates cell proliferation in some cases of TNBC and may be a potential target of molecular therapy for TNBC., (© 2019 S. Karger AG, Basel.)

Nitrophorins (NP) 1-7 are NO-carrying heme proteins found in the saliva of the blood-sucking insect Rhodnius prolixus. The isoform NP7 displays peculiar properties, such as an abnormally high isoelectric point, the ability to bind negatively charged membranes, and a strong pH sensitivity of NO affinity. A unique trait of NP7 is the presence of Glu in position 27, which is occupied by Val in other NPs. Glu27 appears to be important for tuning the heme properties, but its influence on the pH-dependent NO release mechanism, which is assisted by a conformational change in the AB loop, remains unexplored. Here, in order to gain insight into the functional role of Glu27, we examine the effect of Glu27 → Val and Glu27 → Gln mutations on the ligand binding kinetics using CO as a model. The results reveal that annihilation of the negative charge of Glu27 upon mutation reduces the pH sensitivity of the ligand binding rate, a process that in turn depends on the ionization of Asp32. We propose that Glu27 exerts a through-space electrostatic action on Asp32, which shifts the pKa of the latter amino acid towards more acidic values thus reducing the pH sensitivity of the transition between open and closed states.

Purpose: Paget disease of the breast is a rare cancer that originates from the nipple-areolar complex. It is often overlooked and misdiagnosed as benign chronic eczema of the nipple. We aimed to retrospectively verify whether blood flow analysis using Doppler sonography was useful for detecting the presence of Paget disease., Methods: In this retrospective study, 12 patients with pathologically proven unilateral nipple eczematous lesions (seven with Paget disease and five with simple dermatitis) were included. Nipple blood flow signal was observed using Doppler sonography, and the detected blood flow signals were quantified using digitally recorded images. Quantified blood flow ratio and pathologically examined capillary density were evaluated between affected and unaffected nipples. Findings of mammography, grayscale sonography, and contrast-enhanced magnetic resonance imaging (CE-MRI) were reviewed., Results: In patients with Paget disease, Doppler effects in the affected nipple were more clearly visible than those in the unaffected nipple. These effects were sufficiently visible to identify Paget disease. No obvious effects were observed in the affected and unaffected nipples of simple dermatitis. The quantified blood flow ratio and pathologically examined capillary density were significantly higher for the Paget lesion than those for the non-Paget lesion. The sensitivity of CE-MRI and Doppler sonography was markedly correlated, revealing blood flow changes in the nipple lesions of Paget disease., Conclusion: Doppler sonography visualized the proliferation of blood vessels in Paget lesions. The visualization of increased nipple blood flow using Doppler sonography is a simple and low-cost method that provides useful data for identifying Paget disease during routine medical care.

Sensory type [FeFe] hydrogenases are predicted to play a role in transcriptional regulation by detecting the H 2 level of the cellular environment. These hydrogenases contain the hydrogenase domain with distinct modifications in the active site pocket, followed by a Per-Arnt-Sim (PAS) domain. As yet, neither the physiological function nor the biochemical or spectroscopic properties of these enzymes have been explored. Here, we present the characterization of an artificially maturated, putative sensory [FeFe] hydrogenase from Thermotoga maritima (HydS). This enzyme shows lower hydrogen conversion activity than prototypical [FeFe] hydrogenases and a reduced inhibition by CO. Using FTIR spectroelectrochemistry and EPR spectroscopy, three redox states of the active site were identified. The spectroscopic signatures of the most oxidized state closely resemble those of the H ox state from the prototypical [FeFe] hydrogenases, while the FTIR spectra of both singly and doubly reduced states show large differences. The FTIR bands of both the reduced states are strongly red-shifted relative to the H ox state, indicating reduction at the diiron site, but with retention of the bridging CO ligand. The unique functional and spectroscopic features of HydS are discussed with regard to the possible role of altered amino acid residues influencing the electronic properties of the H-cluster.

Matrix metalloproteinases (MMP) are an important family of proteases which catalyze the degradation of extracellular matrix components. While the mechanism of peptide cleavage is well established, the process of enzyme regeneration, which represents the rate limiting step of the catalytic cycle, remains unresolved. This step involves the loss of the newly formed N-terminus (amine) and C-terminus (carboxylate) protein fragments from the site of catalysis coupled with the inclusion of one or more solvent waters. Here we report a novel crystal structure of membrane type I MMP (MT1-MMP or MMP-14), which includes a small peptide bound at the catalytic Zn site via its C-terminus. This structure models the initial product state formed immediately after peptide cleavage but before the final proton transfer to the bound amine; the amine is not present in our system and as such proton transfer cannot occur. Modeling of the protein, including earlier structural data of Bertini and coworkers [I. Bertini, et al., Angew. Chem., Int. Ed., 2006, 45, 7952-7955], suggests that the C-terminus of the peptide is positioned to form an H-bond network to the amine site, which is mediated by a single oxygen of the functionally important Glu240 residue, facilitating efficient proton transfer. Additional quantum chemical calculations complemented with magneto-optical and magnetic resonance spectroscopies clarify the role of two additional, non-catalytic first coordination sphere waters identified in the crystal structure. One of these auxiliary waters acts to stabilize key intermediates of the reaction, while the second is proposed to facilitate C-fragment release, triggered by protonation of the amine. Together these results complete the enzymatic cycle of MMPs and provide new design criteria for inhibitors with improved efficacy.

Background: Breast cancer-related lymphedema often causes cellulitis and is one of the most common complications after breast cancer surgery. Streptococci are the major pathogens underlying such cellulitis. Among the streptococci, the importance of the Lancefield groups C and G is underappreciated; most cases involve Streptococcus dysgalactiae subspecies equisimilis. Despite having a relatively weak toxicity compared with group A streptococci, Streptococcus dysgalactiae subspecies equisimilis is associated with a mortality rate that is as high as that of group A streptococci in cases of invasive infection because Streptococcus dysgalactiae subspecies equisimilis mainly affects elderly individuals who already have various comorbidities., Case Presentation: An 83-year-old Japanese woman with breast cancer-related lymphedema in her left upper limb was referred to our hospital with high fever and acute pain with erythema in her left arm. She showed septic shock with disseminated intravascular coagulation. Blood culture showed positive results for Streptococcus dysgalactiae subspecies equisimilis, confirming a diagnosis of streptococcal toxic-shock syndrome. She survived after successful intensive care., Conclusions: To the best of our knowledge, this case represents the first report of Streptococcus dysgalactiae subspecies equisimilis-induced streptococcal toxic-shock syndrome in a patient with breast cancer-related lymphedema. Breast cancer-related lymphedema is a common problem, and we must pay attention to invasive streptococcal soft tissue infections, particularly in elderly patients with chronic disease.

Matrix Metalloproteinases (MMPs) are a family of proteolytic enzymes whose endopeptidase activity is dependent on the presence of specific metal ions. MT1-MMP (or MMP-14), which has been implicated in tumor progression and cellular invasion, contains a membrane-spanning region located C-terminal to a hemopexin-like domain and an N-terminal catalytic domain. We recombinantly expressed the catalytic domain of human MT1-MMP in E. coli and purified it from inclusion bodies using a refolding protocol that yielded significant quantities of active protein. Crystals of MT1-MMP were obtained using the vapour diffusion method. Here, we describe the protocols used for crystallization and the data analysis together with the resulting diffraction pattern.

Hydrogenases catalyze the reversible conversion of molecular hydrogen to protons and electrons via a heterolytic splitting mechanism. The active sites of [NiFe] hydrogenases comprise a dinuclear Ni-Fe center carrying CO and CN - ligands. The catalytic activity of the standard (O 2 -sensitive) [NiFe] hydrogenases vanishes under aerobic conditions. The O 2 -tolerant [NiFe] hydrogenases can sustain H 2 oxidation activity under atmospheric conditions. These hydrogenases have very similar active site structures that change the ligand sphere during the activation/catalytic process. An important structural difference between these hydrogenases has been found for the proximal iron-sulphur cluster located in the vicinity of the active site. This unprecedented [4Fe-3S]-6Cys cluster can supply two electrons, which lead to rapid recovery of the O 2 inactivation, to the [NiFe] active site., (© The Authors 2016. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.)

Iron-sulfur clusters form one of the largest and most diverse classes of enzyme cofactors in nature. They may serve as structural factors, form electron transfer chains between active sites and external redox partners, or form components of enzyme active sites. Their specific role is a consequence of the cluster type and the surrounding protein environment. The relative effects of these factors are not completely understood, and it is not yet possible to predict the properties of iron-sulfur clusters based on amino acid sequences or rationally tune their properties to generate proteins with new desirable functions. Here, we generate mutations in a [2Fe-2S] cluster protein, the TmHydC subunit of the trimeric [FeFe]-hydrogenase from Thermotoga maritima, to study the factors that affect its redox potential. Saturation mutagenesis of Val131 was used to tune the redox potential over a 135 mV range and revealed that cluster redox potential and electronic properties correlate with amino acid hydrophobicity and the ability to form hydrogen bonds to the cluster. Proline scanning mutagenesis between pairs of ligating cysteines was used to remove backbone amide hydrogen bonds to the cluster and decrease the redox potential by up to 132 mV, without large structural changes in most cases. However, substitution of Gly83 with proline caused a change of HydC to a [4Fe-4S] cluster protein with a redox potential of -526 mV. Together, these results confirm the importance of hydrogen bonding in tuning cluster redox potentials and demonstrate the versatility of iron-sulfur cluster protein folds at binding different types of clusters.

Nitrophorins (NPs) catalyze the nitrite dismutation reaction that is unprecedented in ferriheme proteins. Despite progress in studying the reaction mechanism, fundamental issues regarding the correlation of the structural features with the nitrite dismutase activity of NPs remain elusive. On the other hand, it has been shown that the nitrite complexes of NPs are unique among those of the ferriheme proteins since some of their electron paramagnetic resonance (EPR) spectra show significant highly anisotropic low spin (HALS) signals with large g max values over 3.2. The origin of HALS signals in ferriheme proteins or models is not well understood, especially in cases where axial ligands other than histidine are present. In this study several mutations were introduced in NP4. The related nitrite coordination and dismutation reaction were investigated. As a result, the EPR spectra of the NP-nitrite complexes were found to be tightly correlated with the extent of heme ruffling and protonation state of the proximal His ligand-dictated by an extended H-bonding network at the heme active site. Furthermore, it is established that the two factors are essential in determining the nitrite dismutase activity of NPs. These results may provide a valuable guide for identifying or designing novel heme proteins with similar activity.

Direct spectroscopic evidence for a hydride bridge in the Ni-R form of [NiFe] hydrogenase has been obtained using iron-specific nuclear resonance vibrational spectroscopy (NRVS). The Ni-H-Fe wag mode at 675 cm(-1) is the first spectroscopic evidence for a bridging hydride in Ni-R as well as the first iron-hydride-related NRVS feature observed for a biological system. Although density function theory (DFT) calculation assisted the determination of the Ni-R structure, it did not predict the Ni-H-Fe wag mode at ∼ 675 cm(-1) before NRVS. Instead, the observed Ni-H-Fe mode provided a critical reference for the DFT calculations. While the overall science about Ni-R is presented and discussed elsewhere, this article focuses on the long and strenuous experimental journey to search for and experimentally identify the Ni-H-Fe wag mode in a Ni-R sample. As a methodology, the results presented here will go beyond Ni-R and hydrogenase research and will also be of interest to other scientists who use synchrotron radiation for measuring dilute samples or weak spectroscopic features.

Triple-negative breast cancer (TNBC) is aggressive, with high risk of visceral metastasis and death. A substantial proportion of patients with TNBC is associated with BRCA mutations, implying that these tumors are sensitive to DNA-damaging agents. We report successful treatment of a metastatic TNBC in a woman with a BRCA2 germline mutation using combined bevacizumab/paclitaxel/carboplatin (BPC) therapy. The patient was pregnant and had liver metastases, and a complete clinical response was sustained for approximately 5 years. Mastectomy was performed during the 29th week of pregnancy, and the baby was later delivered by caesarean section. Subsequently, multiple metastases in both liver lobes were detected using computed tomography and magnetic resonance imaging and the patient was treated with a BPC regimen, which led to complete disappearance of metastatic lesions in the liver. No additional treatment was provided, and after 5 years the patient consented to direct sequencing of BRCA2 and a 6781delG mutation was identified. At the most recent (5-year) follow-up, the patient was alive with good quality of life and no evidence of metastases.This finding suggests that BPC therapy might be considered a good therapeutic option for the treatment of metastatic TNBC in a woman with a BRCA2 germline mutation.

The metabolism of many anaerobes relies on [NiFe]-hydrogenases, whose characterization when bound to substrates has proven non-trivial. Presented here is direct evidence for a hydride bridge in the active site of the (57)Fe-labelled fully reduced Ni-R form of Desulfovibrio vulgaris Miyazaki F [NiFe]-hydrogenase. A unique 'wagging' mode involving H(-) motion perpendicular to the Ni(μ-H)(57)Fe plane was studied using (57)Fe-specific nuclear resonance vibrational spectroscopy and density functional theory (DFT) calculations. On Ni(μ-D)(57)Fe deuteride substitution, this wagging causes a characteristic perturbation of Fe-CO/CN bands. Spectra have been interpreted by comparison with Ni(μ-H/D)(57)Fe enzyme mimics [(dppe)Ni(μ-pdt)(μ-H/D)(57)Fe(CO)3](+) and DFT calculations, which collectively indicate a low-spin Ni(II)(μ-H)Fe(II) core for Ni-R, with H(-) binding Ni more tightly than Fe. The present methodology is also relevant to characterizing Fe-H moieties in other important natural and synthetic catalysts.

The two resting forms of the active site of [NiFe] hydrogenase, Ni-A and Ni-B, have significantly different activation kinetics, but reveal nearly identical spectroscopic features which suggest the two states exhibit subtle structural differences. Previous studies have indicated that the states differ by the identity of the bridging ligand between Ni and Fe; proposals include OH(-), OOH(-), H2O, O(2-), accompanied by modified cysteine residues. In this study, we use single crystal ENDOR spectroscopy and quantum chemical calculations within the framework of density functional theory (DFT) to calculate vibrational frequencies, (1)H and (17)O hyperfine coupling constants and g values with the aim to compare these data to experimental results obtained by crystallography, FTIR and EPR/ENDOR spectroscopy. We find that the Ni-A and Ni-B states are constitutional isomers that differ in their fine structural details. Calculated vibrational frequencies for the cyano and carbonyl ligands and (1)H and (17)O hyperfine coupling constants indicate that the bridging ligand in both Ni-A and Ni-B is indeed an OH(-) ligand. The difference in the isotropic hyperfine coupling constants of the β-CH2 protons of Cys-549 is sensitive to the orientation of Cys-549; a difference of 0.5 MHz is observed experimentally for Ni-A and 1.9 MHz for Ni-B, which results from a rotation of 7 degrees about the Cα-Cβ-Sγ-Ni dihedral angle. Likewise, the difference of the intermediate g value is correlated with a rotation of Cys-546 of about 10 degrees.

Introduction: Invasive lobular carcinomas have an increased propensity for distant metastases, particularly to the peritoneum, ovaries, and uterus. In contrast, distant metastases of nonpalpable lobular carcinomas are extremely rare, and the causes of underlying symptoms of primary carcinomas remain unclear. We report a case of an asymptomatic invasive lobular carcinoma with a primary mammary lesion in a patient with rectal stenosis., Case Presentation: A 69-year-old Japanese woman presented to our hospital for treatment of constipation. Although rectal stenosis was confirmed, thorough testing of her lower digestive tract did not identify its cause. Thus, an exploratory laparotomy and tissue biopsy was performed, and the presence of an invasive lobular carcinoma was confirmed. Subsequent breast examinations showed that the invasive lobular carcinoma that led to the rectal stenosis was a metastatic lesion from a primary lesion of the breast duct. As the present breast lobular carcinoma was asymptomatic and nonpalpable, we did not initially consider metastatic breast cancer as a cause of her symptoms, and the final diagnosis was delayed., Conclusions: Peritoneal metastasis from nonpalpable invasive lobular carcinomas is very rare. However, breast cancer metastasis should be considered when carcinomatous peritonitis is present in a patient with an unknown primary cancer.

The enzyme hydrogenase reversibly converts dihydrogen to protons and electrons at a metal catalyst. The location of the abundant hydrogens is of key importance for understanding structure and function of the protein. However, in protein X-ray crystallography the detection of hydrogen atoms is one of the major problems, since they display only weak contributions to diffraction and the quality of the single crystals is often insufficient to obtain sub-ångström resolution. Here we report the crystal structure of a standard [NiFe] hydrogenase (∼91.3 kDa molecular mass) at 0.89 Å resolution. The strictly anoxically isolated hydrogenase has been obtained in a specific spectroscopic state, the active reduced Ni-R (subform Ni-R1) state. The high resolution, proper refinement strategy and careful modelling allow the positioning of a large part of the hydrogen atoms in the structure. This has led to the direct detection of the products of the heterolytic splitting of dihydrogen into a hydride (H(-)) bridging the Ni and Fe and a proton (H(+)) attached to the sulphur of a cysteine ligand. The Ni-H(-) and Fe-H(-) bond lengths are 1.58 Å and 1.78Å, respectively. Furthermore, we can assign the Fe-CO and Fe-CN(-) ligands at the active site, and can obtain the hydrogen-bond networks and the preferred proton transfer pathway in the hydrogenase. Our results demonstrate the precise comprehensive information available from ultra-high-resolution structures of proteins as an alternative to neutron diffraction and other methods such as NMR structural analysis.

Nitrophorins represent a unique class of heme proteins that are able to perform the delicate transportation and release of the free-radical gaseous messenger nitric oxide (NO) in a pH-triggered manner. Besides its ability to bind to phospholipid membranes, the N-terminus contains an additional Leu-Pro-Gly stretch, which is a unique sequence trait, and the heme cavity is significantly altered with respect to other nitrophorins. These distinctive features encouraged us to solve the X-ray crystallographic structures of NP7 at low and high pH and bound with different heme ligands (nitric oxide, histamine, imidazole). The overall fold of the lipocalin motif is well preserved in the different X-ray structures and resembles the fold of other nitrophorins. However, a chain-like arrangement in the crystal lattice due to a number of head-to-tail electrostatic stabilizing interactions is found in NP7. Furthermore, the X-ray structures also reveal ligand-dependent changes in the orientation of the heme, as well as in specific interactions between the A-B and G-H loops, which are considered to be relevant for the biological function of nitrophorins. Fast and ultrafast laser triggered ligand rebinding experiments demonstrate the pH-dependent ligand migration within the cavities and the exit route. Finally, the topological distribution of pockets located around the heme as well as from inner cavities present at the rear of the protein provides a distinctive feature in NP7, so that while a loop gated exit mechanism to the solvent has been proposed for most nitrophorins, a more complex mechanism that involves several interconnected gas hosting cavities is proposed for NP7.

Membrane type 1 matrix metalloproteinase (MT1-MMP) belongs to the large family of zinc-dependent endopeptidases termed MMPs that are located in the extracellular matrix. MT1-MMP was crystallized at 277 K using the vapour-diffusion method with PEG as a precipitating agent. Data sets for MT1-MMP were collected to 2.24 Å resolution at 100 K. The crystals belonged to space group P4(3)2(1)2, with unit-cell parameters a = 62.99, c = 122.60 Å. The crystal contained one molecule per asymmetric unit, with a Matthews coefficient (VM) of 2.90 Å(3) Da(-1); the solvent content is estimated to be 57.6%.

The nitrophorins (NPs) comprise a group of NO transporting ferriheme b proteins found in the saliva of the blood sucking insect Rhodnius prolixus . In contrast to other nitrophorins (NP1-4), the recently identified membrane binding isoform NP7 tends to form oligomers and precipitates at higher concentrations in solution. Hence, solid-state NMR (ssNMR) was employed as an alternative method to gain structural insights on the precipitated protein. We report the expression and purification of (13)C,(15)N isotopically labeled protein together with the first ssNMR characterization of NP7. Because the size of NP7 (21 kDa) still provides a challenge for ssNMR, the samples were reverse labeled with Lys and Val to reduce the number of crosspeaks in two-dimensional spectra. The two electronic spin states with S = 1/2 and S = 0 at the ferriheme iron were generated by the complexation with imidazole and NO, respectively. ssNMR spectra of both forms are well resolved, which allows for sequential resonance assignments of 22 residues. Importantly, the ssNMR spectra demonstrate that aggregation does not affect the protein fold. Comparison of the spectra of the two electronic spin states allows the determination of paramagnetically shifted cross peaks due to pseudocontact shifts, which assists the assignment of residues close to the heme center.

Hydrogenase proteins catalyze the reversible conversion of molecular hydrogen to protons and electrons. The most abundant hydrogenases contain a [NiFe] active site; these proteins are generally biased towards hydrogen oxidation activity and are reversibly inhibited by oxygen. However, there are [NiFe] hydrogenase that exhibit unique properties, including aerobic hydrogen oxidation and preferential hydrogen production activity; these proteins are highly relevant in the context of biotechnological devices. This review describes four classes of these "nonstandard" [NiFe] hydrogenases and discusses the electrochemical, spectroscopic, and structural studies that have been used to understand the mechanisms behind this exceptional behavior. A revised classification protocol is suggested in the conclusions, particularly with respect to the term "oxygen-tolerance". This article is part of a special issue entitled: metals in bioenergetics and biomimetics systems., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: Third-generation aromatase inhibitors(AIs)are now common in adjuvant hormone therapy for breast cancer in postmenopausal women. However, a suitable treatment has yet to be established for patients who develop cancer recurrence during or after adjuvant AI therapy., Patients and Methods: This prospective study evaluated the efficacy and safety of 120mg/day toremifene citrate(TOR-120)administered orally to 23 patients with recurrent breast cancer who were receiving or had received adjuvant AI therapy. Primary therapy for recurrence was TOR-120 monotherapy., Results: The response rate was 13. 0%(partial response: three patients), the clinical benefit rate was 78. 3%(partial response: three patients; long-term stable disease: 15 patients), and median time to progression was 8. 1 months. Grade 1 adverse events such as loss of appetite, sweating, flushing and edema face were observed., Conclusion: TOR-120 monotherapy was effective and safe as a primary hormone therapy for recurrent breast cancer unresponsive to AIs.

Nitrophorins are proteins occurring in the saliva of the blood-sucking insect Rhodnius prolixus to carry NO as a vasodilator and blood-coagulation inhibitor into the victim's tissue. It was suggested that the rate of NO release can be enhanced by the blood-plasma component L-cysteine [J.M.C.Ribeiro, Insect Biochem. Mol. Biol. 26 (1996) 899-905]. However, the mechanism of the reaction is not clear. In the attempt to exploit the reaction in detail, complexes of nitrophorin 4 (NP4) with the thiols 2-mercaptoethanol, L-cysteine, and L-homocysteine and with HS(-) were formed and characterized under anaerobic conditions using absorption spectroscopy, X-ray crystallography, and EPR spectroscopy. In contrast to met-myoglobin, which is reduced by L-cysteine, all four compounds form low-spin Fe(III) complexes with NP4. The weak equilibration constants (167-5200 M(-1)) neither support significant complexation nor the simple displacement of NO in vivo. Both amino acid based thiols form additional H-bonds with side chains of the heme pocket entry. Glutathione and L-methionine did not form a complex, indicating the specificity of the complexes with L-cysteine and L-homocysteine. Continuous wave EPR spectroscopy reveals the simultaneous existence of three low-spin systems in each case that are attributed to various protonation and/or conformational stages in the heme pocket. Electron nuclear double resonance (ENDOR) spectroscopy demonstrates that the thiol sulfurs are, at least in part, protonated. Overall, the results not only demonstrate the good accessibility of the NP4 heme center by biologically relevant thiols, but also represent the first structural characterization of a ferriheme protein in complex with L-cysteine L-homocysteine., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Nuclear inelastic scattering of (57)Fe labeled [NiFe] hydrogenase is shown to give information on different states of the enzyme. It was thus possible to detect and assign Fe-CO and Fe-CN bending and stretching vibrations of the active site outside the spectral range of the Fe-S cluster normal modes., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Heme proteins are important entities for the metabolism of nitrite. Inspection of the structural features of the reported hemoprotein-nitrite crystal structures reveals that, except for nitrophorin 4 (NP4), H-bonding to the nitrite ligand is accomplished via histidine or arginine residues. These H-bonds probably play an important role for the nitrite coordination and/or reactivities. In nitrophorins, which catalyze the nitrite disproportionation reaction, such a residue is missing. Here, we report on the L130R mutant of the NP isoprotein NP4 that provides the Arg130 residue as part of the flexible G-H loop as a potential H-bonding residue in the distal heme pocket. Similar to the wild-type protein, nitrite remains N-bonded in the crystal structure of NP4(L130R). However, spectroscopic investigations show that, in solution, a second ligand-rotational orientation exists, which is in fast-exchange equilibrium with the normal, parallel ligand orientation. Moreover, the nitrite disproportionation is inhibited in NP4(L130R). Comparison with another, also less active mutant NP4(D30N) suggests that the displacement of H(2)O molecules from the heme cavity prevents the proton donation pathway through Asp30., (Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich.)

NO is an important signaling molecule in human tissue. However, the mechanisms by which this molecule is controlled and directed are currently little understood. Nitrophorins (NPs) comprise a group of ferriheme proteins originating from blood-sucking insects that are tailored to protect and deliver NO via coordination to and release from the heme iron. Therefore, the kinetics of the association and dissociation reactions were studied in this work using the ferroheme-CO complexes of NP4, NP4(D30N), and NP7 as isoelectronic models for the ferriheme-NO complexes. The kinetic measurements performed by nanosecond laser-flash-photolysis and stopped-flow are accompanied by resonance Raman and FT-IR spectroscopy to characterize the carbonyl species. Careful analysis of the CO rebinding kinetics reveals that in NP4 and, to a larger extent, NP7 internal gas binding cavities are located, which temporarily trap photodissociated ligands. Moreover, changes in the free energy barriers throughout the rebinding and release pathway upon increase of the pH are surprisingly small in case of NP4. Also in case of NP4, a heterogeneous kinetic trace is obtained at pH 7.5, which corresponds to the presence of two carbonyl species in the heme cavity that are seen in vibrational spectroscopy and that are due to the change of the distal heme pocket polarity. Quantification of the two species from FT-IR spectra allowed the fitting of the kinetic traces as two processes, corresponding to the previously reported open and closed conformation of the A-B and G-H loops. With the use of the A-B loop mutant NP4(D30N), it was confirmed that the kinetic heterogeneity is controlled by pH through the disruption of the H-bond between the Asp30 side chain and the Leu130 backbone carbonyl. Overall, this first study on the slow phase of the dynamics of diatomic gas molecule interaction with NPs comprises an important experimental contribution for the understanding of the dynamics involved in the binding/release processes of NO/CO in NPs.

A 39-year-old premenopausal nulliparous woman presented with severe pain in her right breast, bleeding and pus-like discharge, and a deep ulcer approximately 18 cm in diameter.Contralateral breast metastasis, bilateral axillary lymph node metastases, and multiple lung and bone metastases were detected on computed tomography.Five years previously she had undergone surgery for ovarian cancer and had prematurely discontinued adjuvant chemotherapy because of side effects. Following the administration of pain control, the patient received trastuzumab(Tr)plus vinorelbine(VNR)for her breast cancer as first-line therapy to avoid hair loss.The ulcer on her right chest wall underwent complete epithelialization and the patient's performance status improved from 3 to 0.The pus-like discharge, pain, bleeding, and odor from the breast resolved completely, and 5 months later, her quality of life had improved.The lung metastases also resolved completely.No adverse affects, including hematotoxicity and hair loss, were seen until treatment failure 12.5 months later. Second-line and third-line treatments were performed, but brain metastases developed, and the patient's overall condition deteriorated because of the development of ileus of unknown etiology.She died 21 months later.The patient received all therapies on an outpatient basis. Combination therapy using Tr and VNR is superior in safety and tolerability, and has been considered an option for first-line treatment of metastatic, locally advanced HER2-positive breast cancer.

Nitrophorins (nitric oxide transport proteins) are haemproteins originating from the blood-feeding insect Rhodnius prolixus. They consist of an eight-stranded β-barrel, which classifies them into the lipocalin family. Nitrophorin 7 (NP7) and the E27V mutant protein NP7(E27V) were crystallized at 277 K using the vapour-diffusion method with PEG as the precipitating agent. Data sets for wild-type NP7 and NP7(E27V) were collected to 1.80 Å resolution from single crystals at 100 K using synchrotron radiation. The crystals belonged to space group P2(1), with unit-cell parameters a = 38, b = 67, c = 39 Å, β = 117°. The crystal contained one molecule per asymmetric unit, with a Matthews coefficient (V(M)) of 2.11 Å(3) Da(-1); the solvent content was estimated to be 41.8%., (© 2012 International Union of Crystallography. All rights reserved.)

Dissimilatory sulfite reductase (Dsr) plays an important role in sulfate respiration in many sulfate-reducing bacteria. Dsr from Desulfovibrio vulgaris Miyazaki F has been purified and crystallized at 277 K using the sitting-drop vapour-diffusion method with PEG 3350 and potassium thiocyanate as precipitants. A data set was collected to 3.7 Å resolution from a single crystal at 100 K using synchrotron radiation. The Dsr crystal belonged to space group P4(1)2(1)2, with unit-cell parameters a = b = 163.26, c = 435.32 Å. The crystal structure of Dsr was determined by the molecular-replacement method based on the three-dimensional structure of Dsr from D. vulgaris Hildenborough. The crystal contained three α(2)β(2)γ(2) units per asymmetric unit, with a Matthews coefficient (V(M)) of 2.35 Å(3) Da(-1); the solvent content was estimated to be 47.7%.

The crystal structure of the membrane-associated [NiFe] hydrogenase from Allochromatium vinosum has been determined to 2.1 Å resolution. Electron paramagnetic resonance (EPR) and Fourier transform infrared spectroscopy on dissolved crystals showed that it is present in the Ni-A state (>90%). The structure of the A. vinosum [NiFe] hydrogenase shows significant similarities with [NiFe] hydrogenase structures derived from Desulfovibrio species. The amino acid sequence identity is ∼ 50%. The bimetallic [NiFe] active site is located in the large subunit of the heterodimer and possesses three diatomic non-protein ligands coordinated to the Fe (two CN(-) , one CO). Ni is bound to the protein backbone via four cysteine thiolates; two of them also bridge the two metals. One of the bridging cysteines (Cys64) exhibits a modified thiolate in part of the sample. A mono-oxo bridging ligand was assigned between the metal ions of the catalytic center. This is in contrast to a proposal for Desulfovibrio sp. hydrogenases that show a di-oxo species in this position for the Ni-A state. The additional metal site located in the large subunit appears to be a Mg(2+) ion. Three iron-sulfur clusters were found in the small subunit that forms the electron transfer chain connecting the catalytic site with the molecular surface. The calculated anomalous Fourier map indicates a distorted proximal iron-sulfur cluster in part of the crystals. This altered proximal cluster is supposed to be paramagnetic and is exchange coupled to the Ni(3+) ion and the medial [Fe(3)S(4)](+) cluster that are both EPR active (S=1/2 species). This finding of a modified proximal cluster in the [NiFe] hydrogenase might explain the observation of split EPR signals that are occasionally detected in the oxidized state of membrane-bound [NiFe] hydrogenases as from A. vinosum., (Copyright © 2010 Elsevier Ltd. All rights reserved.)