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Background: The number of hemodialysis (HD) patients is increasing worldwide, and they are at a higher risk of cancer than the general population. Because HD patients are more likely to have inflammation, radiotherapy (RT)-induced adverse effects (AEs) are theoretically expected to be worse for HD patients. Since only a few reports have been published on this subject, we aimed to evaluate the tolerability of RT in HD patients. Methods: We retrospectively analyzed AEs related to RT for HD patients. Our study included patients from three institutions treated between January 2007 and July 2017. The patient eligibility criteria were (i) receipt of maintenance HD 2–3 times per week for end-stage renal disease prior to the start of RT and (ii) pathologically confirmed malignancies. The endpoints were acute and late non-hematologic AEs. Results: The study included 56 patients. The most common histology was head and neck cancer (23%), followed by lung cancer (14%) and prostate cancer (11%). The median radiation dose was 60 (range, 12–93.8) Gy at an equivalent dose in 2-Gy fractions (EQD2). The RT completion rate was 96%. Patients had a median follow-up period after RT of 9.1 (range 0.5–98.1) months. Grade 3 or worse acute and late AEs were noted in 6 (11%) and 3 (7%) patients, respectively. In the acute phase, 2 patients had grade 5 AEs, both of which were infections. Conclusion: Our results suggest that RT for HD patients is clinically tolerable. However, some patients can experience severe infections related to treatment. [ABSTRACT FROM AUTHOR]

The structure of cyclic sialyl 6-sulfo Lewis x, a new biologically dormant form of L-selectin ligand, was determined unambiguously by the accurate NMR analysis to have the lactamized B conformation of its sialic acid. For the NMR structure elucidation were used various informations, such as chemical shifts values, appearance of amide proton, and NOE. [Copyright &y& Elsevier]

Presents a study on the isolation of our antifouling secosteroids, isogosterones A-D, from a Japanese octocoral Dendronephthya sp. Determination of the structures of the four isogosterones; Stereochemistry of isogosterones; Hemiacetal or acetal functionality of the isogosterones; Antifouling activity of the steroids.

Two major structural genomics projects exist in Japan. The oldest, the RIKEN Structural Genomics Initiative, has two major goals: to determine bacterial, mammalian, and plant protein structures by X-ray crystallography and NMR spectroscopy and to perform functional analyses with the target proteins. The newest, the structural genomics project at the Biological Information Research Center, focuses on human membrane proteins. [ABSTRACT FROM AUTHOR]

Highlights • 4-Methyl-5-oxo-octane-1,8-dioic acid was isolated as a metabolite of steroid degradation in Comamonas testosteroni. • Experiments indicated that 4-methyl-5-oxo-2-octene-1,8-dioic acid was also a metabolite. • ORF3(scdN)-encoded CoA-hydratase was indicated to convert CoA-ester of 4-methyl-5-oxo-2-octene-1,8-dioic acid. Abstract Comamonas testosteroni TA441 degrades steroids via 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid, which is presumed to be further degraded by β-oxidation. In the β-oxidation process, Coenzyme A (CoA)-ester of 9-oxo-1,2,3,4,5,6,10,19-octanor-13,17-secoandrost-8(14)-ene-7,17-dioic acid is produced and converted by β-ketoacyl-CoA-transferase encoded by ORF1 and ORF2 (scdL1L2) to cleave the remaining C-ring. In this study, we isolated and identified 4-methyl-5-oxo-octane-1,8-dioic acid and 4-methyl-5-oxo-3-octene-1,8-dioic acid from the culture of the ORF3 (scdN)-null mutant as metabolites of steroid degradation (ADD and cholic acid analogues; cholic acid, chenodeoxycholic acid, deoxycholic acid, and lithocholic acid). In addition of these compounds, UHPLC/MS analysis of the culture of the scdN -null mutant revealed significant accumulation of another compound, which was detected as a dominant peak of m/z 155 ([M−CO 2 ]−) accompanied by a small peak of parental ion (m/z 199 [M−]). On the bases of experimental data, this compound was presumed to be 4-methyl-5-oxo-2-octene-1,8-dioic acid, whose CoA-ester was indicated to be converted by scdN -encoded CoA-hydratase into the CoA-ester of 3-hydroxy-4-methyl-5-oxooctan-1,7-carboxylic acid. [ABSTRACT FROM AUTHOR]

Tetramic acid containing a decalin ring such as equisetin and phomasetin is one of the characteristic scaffolds found in fungal bioactive secondary metabolites. Polyketide (PKS)-nonribosomal peptide synthetase (NRPS) hybrid enzyme is responsible for the synthesis of the polyketide scaffold conjugated with an amino acid. PKS-NRPS hybrid complex programs to create structural diversity in the polyketide backbone have begun to be investigated, yet mechanism of control of the stereochemistry in a decalin formation via a Diels-Alder cycloaddition remains uncertain. Here, we demonstrate that fsa2 , which showed no homology to genes encoding proteins of known function, in the fsa cluster responsible for equisetin and fusarisetin A biosynthesis in Fusarium sp. FN080326 , is involved in the control of stereochemistry in decalin formation via a Diels-Alder reaction in the equisetin biosynthetic pathway. [ABSTRACT FROM AUTHOR]

Summary: Terpendole E is the first natural product inhibitor of kinesin Eg5. Because terpendole E production is unstable, we isolated and analyzed the terpendole E biosynthetic gene cluster, which consists of seven genes encoding three P450 monooxygenases (TerP, TerQ, and TerK), an FAD-dependent monooxygenase (TerM), a terpene cyclase (TerB), and two prenyltransferases (TerC and TerF). Gene knockout and feeding experiments revealed that terpendole E is a key intermediate in terpendole biosynthesis and is produced by the action of the key enzyme TerQ from paspaline, a common biosynthetic intermediate of indole-diterpenes. TerP converts terpendole E to a downstream intermediate specific to terpendole biosynthesis and converts paspaline to shunt metabolites. We successfully overproduced terpendole E by disrupting the terP gene. We propose that terpendole E is a key biosynthetic intermediate of terpendoles and related indole-diterpenes. [ABSTRACT FROM AUTHOR]

Summary: Marine sponges contain structurally intriguing and biologically active peptides of nonribosomal peptide synthase origin, often containing amino acids with novel structures. Here we report the discovery of asteropine A (APA), a cystine knot to be isolated from marine sponges. The solution structure of APA as determined by NMR belongs to the four-loop class of cystine knots similar to those of some conotoxins and spider toxins. However, the highly negatively charged surface of APA is uncommon among other cystine knots. APA competitively inhibits bacterial sialidases, but not a viral sialidase. APA was inactive against all other enzymes tested and did not have any apparent antitumor activity. Our data suggest that APA and other knotting peptides may be important leads for antibacterial and even antiviral drug development. [Copyright &y& Elsevier]

Abstract: Tubiferal A, a novel rearranged triterpenoid lactone, has been isolated from field-collected fruit bodies of the myxomycete, Tubifera dimorphotheca, and its structure elucidated by spectral data. Tubiferal A (1) possesses a 9,10-secocycloartan-16,21-olide skeleton, and this new compound exhibited a reversal effect of vincristine (VCR) resistance (more than 4-fold) against VCR-resistant KB cell lines. Tubiferal B (2), corresponding to the seco acid of 1 was also isolated, but showed no comparable activity. [Copyright &y& Elsevier]

Examines the larval metamorphosis-inducing substance in the ascidian Halocynthia roretzi. Isolation of lumichrome; Assay for larval metamorphosis; Measurement of fluorescence spectrum.

Pyricularia oryzae is one of the most devastating plant pathogens in the world. This fungus produces several secondary metabolites including the phytotoxin pyriculols, which are classified into 2 types: aldehyde form (pyriculol and pyriculariol) and alcohol form (dihydropyriculol and dihydropyriculariol). Although interconversion between the aldehyde form and alcohol form has been predicted, and the PYC10 gene for the oxidation of alcohol form to aldehyde is known, the gene responsible for the reduction of aldehyde to alcohol form is unknown. Furthermore, previous studies have predicted that alcohol analogs are biosynthesized via aldehyde analogs. Herein, we demonstrated that an aldo/keto reductase PYC7 is responsible for the reduction of aldehyde to alcohol congeners. The results indicate that aldehyde analogs are biosynthesized via alcohol analogs, contradicting the previous prediction. The results suggest that P. oryzae controls the amount of pyriculol analogs using two oxidoreductases, PYC7 and PYC10, thereby controlling the bioactivity of the phytotoxin. [ABSTRACT FROM AUTHOR]

We identified the biosynthetic gene cluster for lucilactaene, a cell cycle inhibitor from a filamentous fungus Fusarium sp. RK 97–94. The luc1 knockout strain accumulated demethylated analogs, indicating the involvement of Luc1 methyltransferase in lucilactaene biosynthesis. Lucilactaene showed potent antimalarial activity. Our data suggested that methylation and ether ring formation are essential for its potent antimalarial activity. [ABSTRACT FROM AUTHOR]

Highlights • Metabolites of steroids with only C-ring were identified from Comamonas testosterone. • 9-Oxo-1,2,3,4,5,6,10,19-octanor-13,17-secoandrost-8(14)-ene-7,17-dioic acid was isolated. • ORF1 and 2-encoded-CoA-transferase (ScdL1L2) converts CoA-ester of this compound. Abstract Comamonas testosteroni TA441 degrades steroid compounds via aromatization of the A-ring to produce 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid (a metabolite with C- and D-rings), which is presumed to be further degraded via β-oxidation. In elucidating the complete steroid degradation process in C. testosteroni , we isolated 9-oxo-1,2,3,4,5,6,10,19-octanor-13,17-secoandrost-8(14)-ene-7,17-dioic acid and several other metabolites containing only C-ring. For conversion of the CoA-ester of this compound, a two-subunit β -ketoacyl-CoA-transferase encoded by ORF1 and ORF2 was shown to be indispensable. ORF1 and ORF2 are located just after tesB , the meta -cleavage enzyme gene in one of the two major steroid degradation gene clusters of strain TA441. Conversion by the CoA-transferase leads to cleavage of the remaining C-ring, and the product was suggested to be further degraded by β-oxidation involving other genes in the cluster. ORF1 and ORF2 are considered orthologues of ipdAB gene in Mycobacterium tuberculosis H37Rv, which is recently reported as the CoA-transferase of 9-oxo-1,2,3,4,5,6,10,19-octanor-13,17-secoandrost-8(14)-ene-7,17-dioic acid (Crowe AM, Casabon I, Brown KL, Liu J, Lian J, Rogalski JC, Hurst TE, Snieckus V, Foster LJ, Eltis LD. 2017. MBio 8). [ABSTRACT FROM AUTHOR]

Single amino acid potential (SAAP) would be a prominent factor to determine peptide conformations. To prove this hypothesis, we previously developed SAAP force field for molecular simulation of polypeptides. In this study, the force field was renovated to SAAP3D force field by applying more accurate three-dimensional main-chain parameters, instead of the original two-dimensional ones, for the amino acids having a long side-chain. To demonstrate effectiveness of the SAAP3D force field, replica-exchange Monte Carlo (REMC) simulation was performed for two benchmark short peptides, chignolin (H-GYDPETGTWG-OH) and C-peptide (CHO-AETAAAKFLRAHA-NH). For chignolin, REMC/SAAP3D simulation correctly produced native β-turn structures, whose minimal all-atom root-mean-square deviation value measured from the native NMR structure (except for H) was 1.2 Å, at 300 K in implicit water, along with misfolded β-hairpin structures with unpacked aromatic side chains of Tyr2 and Trp9. Similar results were obtained for chignolin analog [G1Y,G10Y], which folded more tightly to the native β-turn structure than chignolin did. For C-peptide, on the other hand, the α-helix content was larger than the β content on average, suggesting a significant helix-forming propensity. When the imidazole side chain of His12 was protonated (i.e., [His12Hip]), the α content became larger. These observations as well as the representative structures obtained by clustering analysis were in reasonable agreement not only with the structures of C-peptide that were determined in this study by NMR in 30% CDCD in HO at 298 K but also with the experimental and theoretical behaviors having been reported for protonated C-peptide. Thus, accuracy of the SAAP force field was improved by applying three-dimensional main-chain parameters, supporting prominent importance of SAAP for peptide conformations. [ABSTRACT FROM AUTHOR]

During the chemical investigation of marine-derived fungus, an unusual diketopiperazine (DKP) alkaloid, haenamindole ( 1 ), was isolated from a culture of the marine-derived fungus Penicillium sp. KCB12F005. The structure of 1 , which possesses benzyl-hydroxypiperazindione and phenyl-pyrimidoindole rings system in the molecule, was elucidated by analysis of NMR and MS data. The stereochemistry of 1 was determined by ROESY and advanced Marfey’s method. [ABSTRACT FROM AUTHOR]

Four possible stereoisomers of a model compound of highly O-bearing bisabolane sesquiterpenes were synthesized and their NMR spectra were compared. Starting from isopulegol, allylic oxidation and Grignard reaction afforded a mixture of alcohols at C(8), which was separated. After metathesis reaction, both α- and β-epoxides were obtained via non-stereoselective epoxidation, while VO(OiPr)3-catalyzed epoxidation afforded a single diastereoisomer selectively. NMR Spectra of twelve synthesized compounds, four stereoisomers of acetates, isobutyrates, and tiglates, were measured. A difference between C(8 α)- and C(8 β)-acyloxy isomers was observed in the δ-values of HC(8) in CDCl3. Within the 8 β-acyloxy compounds, the α- and the β-epoxides were distinguished by either the J-value of HC(8) or the chemical shift of CH2(9). Within the 8 α-acyloxy compounds, two epoxide isomers were distinguished by the J-value of HC(10) in C6D6 or in CD3OD. [ABSTRACT FROM AUTHOR]

Comamonas testosteroni degrades testosterone into 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid and 2-hydroxyhexa-2,4-dienoic acid via aromatization of the A-ring. The former compound is suggested to be degraded further by β-oxidation, but the details of the process remain unclear. In this study, we identified 9α-hydroxy-17-oxo-1,2,3,4,10,19-hexanorandrost-6-en-5-oic acid as an intermediate compound in the β-oxidation of this compound. ORF32, located in one of the two main steroid degradation gene clusters, was shown to be indispensable for the conversion of this compound. A homology search indicated that ORF32 encodes a hydratase for the CoA-ester, suggesting that ORF32 encodes a hydratase that adds a water molecule to a double bond at C-6 of the CoA-ester of 9α-hydroxy-17-oxo-1,2,3,4,10,19-hexanorandrost-6-en-5-oic acid. From the culture of an ORF32-disrupted mutant incubated with cholic acid for a short period (around two days, when a considerable number of intermediate compounds were detected by HPLC), 7α,12α-dihydroxy-3-oxochola-1,4-dien-24-oic acid, 7α,12α-dihydroxy-3-oxochol-4-en-24-oic acid, 12α-hydroxy-3-oxochola-4,6-dien-24-oic acid, 7α,12α-dihydroxy-3-oxopregna-1,4-diene-20-carboxylic acid, 12α-hydroxy-3-oxopregna-4,6-diene-20-carboxylic acid, 7α,12α-dihydroxy-3-oxopregn-4-ene-20-carboxylic acid, 12α-hydroxy-3-oxopregna-4,6-diene-20-carboxylic acid, 7α-hydroxy-3-oxopregna-4,17(20)-diene-20-carboxylic acid, and 3-oxopregna-4,6,17(20)-triene-20-carboxylic acid were isolated as intermediate compounds of C-17 side-chain degradation. The presence of these compounds implies that the process of degradation of the C-17 side chain in C. testosteroni will be similar to the process in Pseudomonas. The final two compounds, which have a double bond at the C-17(20) position, are here identified for the first time, to the best of our knowledge, as intermediate compounds in bacterial steroid degradation; their composition suggests that the remaining three carbons at the C-17 position would be removed oxidatively as a propionic acid derivative. [ABSTRACT FROM AUTHOR]

This report describes that a regular positive electrospray ionization mass spectrometry (MS) analysis of terpendoles often causes unexpected oxygen additions to form [M + H + O]+ and [M + H + 2O]+, which might be a troublesome in the characterization of new natural analogues. The intensities of [M + H + O]+ and [M + H + 2O]+ among terpendoles were unpredictable and fluctuated largely. Simple electrochemical oxidation in electrospray ionization was insufficient to explain the phenomenon. So we studied factors to form [M + H + O]+ and [M + H + 2O]+ using terpendole E and natural terpendoles together with some model indole alkaloids. Similar oxygen addition was observed for 1,2,3,4-tetrahydrocyclopent[ b]indole, which is corresponding to the substructure of terpendole E. In tandem MS experiments, a major fragment ion at m/z 130 from protonated terpendole E was assigned to the substructure containing indole. When the [M + H + O]+ was selected as a precursor ion, the ion shifted to m/z 146. The same 16 Da shift of fragments was also observed for 1,2,3,4-tetrahydrocyclopent[ b]indole, indicating that the oxygen addition of terpendole E took place at the indole portion. However, the oxygen addition was absent for some terpendoles, even whose structure resembles terpendole E. The breakdown curves characterized the tandem MS features of terpendoles. Preferential dissociation into m/z 130 suggested the protonation tendency at the indole site. Terpendoles that are preferentially protonated at indole tend to form oxygen addition peaks, suggesting that the protonation feature contributes to the oxygen additions in some degrees. © 2014 The Authors. Journal of Mass Spectrometry published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article discusses the identification of catalytic amino acid residues of the enzyme lachrymatory factor synthase (LFS) present in onions. It mentions that LFS enzymes synthesizes lachrymatory factor which produces the compound thioaldehyde S-oxides. The two amino acids arginine and glutamic acid were recognized to be essential for LFS activities that were identified through various techniques which include deletion analysis, homology modeling and site-directed mutagenesis.

Zinc (Zn) is an essential trace metal required by many enzymes and transcription factors for their activity or the maintenance of their structure. Zn has a variety of effects in the immune responses and inflammation, although it has not been well known how Zn affects these reactions on the molecular basis. We here showed that Zn suppresses Th17-mediated autoimmune diseases at lest in part by inhibiting the development of Th17 cells via attenuating STAT3 activation. In mice injected with type II collagen to induce arthritis, Zn treatment inhibited Th17 cell development. IL-6-mediated activation of STAT3 and in vitro Th17 cell development were all suppressed by Zn. Importantly, Zn binding changed the α-helical secondary structure of STAT3, disrupting the association of STAT3 with JAK2 kinase and with a phospho-peptide that included a STAT3-binding motif from the IL-6 signal transducer gp130. Thus, we conclude that Zn suppresses STAT3 activation, which is a critical step for Th17 development. [ABSTRACT FROM PUBLISHER]

Abstract: We report a solid-state 17O NMR study of the 17O electric-field-gradient (EFG) and chemical shielding (CS) tensors for each carboxylate group in polycrystalline l-alanine and l-phenylalanine. The magic angle spinning (MAS) and stationary 17O NMR spectra of these compounds were obtained at 9.4, 14.1, and 16.4T. Analyzes of these 17O NMR spectra yielded reliable experimental NMR parameters including 17O CS tensor components, 17O quadrupole coupling parameters, and the relative orientations between the 17O CS and EFG tensors. The extensive quantum chemical calculations at both the restricted Hartree–Fock and density-functional theories were carried out with various basis sets to evaluate the quality of quantum chemical calculations for the 17O NMR tensors in l-alanine. For 17O CS tensors, the calculations at the B3LYP/D95∗∗ level could reasonably reproduce 17O CS tensors, but they still showed some discrepancies in the δ 11 components by approximately 36ppm. For 17O EFG calculations, it was advantageous to use calibrated Q value to give acceptable C Q values. The calculated results also demonstrated that not only complete intermolecular hydrogen-bonding networks to target oxygen in l-alanine, but also intermolecular interactions around the group were significant to reproduce the 17O NMR tensors. [Copyright &y& Elsevier]

Abstract: Several species of ascidians, the so-called tunicates, accumulate extremely high levels of vanadium ions in their blood cells. We previously identified a family of vanadium-binding proteins, named Vanabins, from blood cells and blood plasma of a vanadium-rich ascidian, Ascidia sydneiensis samea. The 3-dimensional structure of Vanabin2, the predominant vanadium-binding protein in blood cells, has been revealed, and the vanadium-binding properties of Vanabin2 have been studied in detail. Here, we used Far Western blotting to identify a novel protein that interacts with Vanabin2 from a blood cell cDNA library. The protein, named Vanabin-interacting protein 1 (VIP1), was localized in the cytoplasm of signet ring cells and giant cells. Using a two-hybrid method, we revealed that VIP1 interacted with Vanabins 1, 2, 3, and 4 but not with Vanabin P. The N-terminal domain of VIP1 was shown to be important for the interaction. Further, Vanabin1 was found to interact with all of the other Vanabins. These results suggest that VIP1 and Vanabin1 act as metal chaperones or target proteins in vanadocytes. [Copyright &y& Elsevier]

It has been assumed that the π-electrons of aromatic residues in the catalytic sites of triterpene cyclases stabilize the cationic intermediates formed during the polycyclization cascade of squalene or oxidosqualene, but no definitive experimental evidence has been given. To validate this cation-π interaction, natural and unnatural aromatic amino acids were site-specifically incorporated into squalene-hopene cyclase (SHC) from Alicyclobacillus acidocaldarius and the kinetic data of the mutants were compared with that of the wild-type SHC. The catalytic sites of Phe365 and Phe605 were substituted with O-methyltyrosine, tyrosine, and tryptophan, which have higher cation-π binding energies than phenylalanine. These replacements actually increased the SHC activity at low temperature, but decreased the activity at high temperature, as compared with the wild-type SHC. This decreased activity is due to the disorganization of the protein architecture caused by the introduction of the amino acids more bulky than phenylalanine. Then, mono-, di-, and trifluorophenylalanines were incorporated at positions 365 and 605; these amino acids reduce cation-π binding energies but have van der Waals radii similar to that of phenylalanine. The activities of the SHC variants with fluorophenylalanines were found to be inversely proportional to the number of the fluorine atoms on the aromatic ring and clearly correlated with the cation-π binding energies of the ring moiety. No serious structural alteration was observed for these variants even at high temperature. These results unambiguously show that the π-electron density of residues 365 and 605 has a crucial role for the efficient polycyclization reaction by SHC. This is the first report to demonstrate experimentally the involvement of cation-π interaction in triterpene biosynthesis. [ABSTRACT FROM AUTHOR]

Abstract: We have presented an experimental investigation of the carboxyl oxygen NMR parameters for four distinct sites in l-valine and l-isoleucine. The carboxyl 17O quadrupolar coupling constant, C Q, and isotropic chemical shift, δ iso, for these compounds are obtained by analyzing two-dimensional 17O multiple-quantum magic-angle spinning (MQMAS) and/or 1D MAS spectra. The values of C Q and δ iso found to be in the range of 7.00–7.85MHz, and 264–314ppm, respectively. Extensive quantum chemical calculations at the density functional levels have been performed for a full cluster of l-valine molecules and a few theoretical models. The calculated results indicated that there was a correlation between the 17O NMR parameters and C–O bond lengths, which was helpful for the spectral assignment. They also demonstrated that the torsion angle of l-valine plays an important role in determining the magnitudes of 17O NMR parameters. [Copyright &y& Elsevier]

Many benthic marine invertebrates, like barnacles, have a planktonic larval stage whose primary purpose is dispersal. How these species colonize suitable substrata is fundamental to understanding their evolution, population biology, and wider community dynamics. Unlike larval dispersal, settlement occurs on a relatively small spatial scale and involves larval behavior in response to physical and chemical characteristics of the substratum. Biogenic chemical cues have been implicated in this process. Their identification, however, has proven challenging, no more so than for the chemical basis of barnacle gregariousness, which was first described >50 years ago. We now report that a biological cue to gregarious settlement, the settlement-inducing protein complex (SIPC), of the major fouling barnacle Balanus amphitrite is a previously undescribed glycoprotein. The SIPC shares a 30% sequence homology with the thioester-containing family of proteins that includes the α2-macroglobulins. The cDNA (5.2 kb) of the SIPC encodes a protein precursor comprising 1,547 aa with a 17-residue signal peptide region. A number of structural characteristics and the absence of a thioester bond in the SIPC suggest that this molecule is a previously undescribed protein that may have evolved by duplication from an ancestral α2-macroglobulin gene. Although the SIPC is regarded as an adult cue that is recognized by the cyprid at settlement, it is also expressed in the juvenile and in larvae, where it may function in larva-larva settlement interactions. [ABSTRACT FROM AUTHOR]

Aequorin, which is a calcium-sensitive photoprotein and a member of the EF-hand superfamily, binds to Mg2+ under physiological conditions, which modulates its light emission. The Mg2+ binding site and its stabilizing influence were examined by NMR spectroscopy. The binding of Mg2+ to aequorin prevented the molecule from aggregating and stabilized it in the monomeric form. To determine the structural differences between Mg2+-bound and free aequorin, we have performed backbone NMR assignments of aequorin in the Mg2+-free state. Mg2+ binding induces conformational changes that are localized in the EF-hand loops. The chemical shift difference data indicated that there are two Mg2+-binding sites, EF-hands I and III. The Mg2+ titration experiment revealed that EF-hand III binds to Mg2+ with higher affinity than EF-hand I, and that only EF-hand III seems to be occupied by Mg2+ under physiological conditions. [ABSTRACT FROM PUBLISHER]

Axinelloside A was isolated from the lipophilic extract of the Japanease marine sponge Axinella infundibula as a strong human telomerase inhibitor (IC50 2.0 μg/mL). It has the molecular weight of 4780.4 as the monoisotopic mass of the 19 sodium salt. The chemical structure was elucidated mainly by spectroscopic methods (2D NMR and MS). Axinelloside A consists of twelve sugars, e.g., a scyllo-inositol, a D-arabinose, 5 D-galactoses, and 5 L-fucoses, together with an (R)-3-hydroxy-octadecanoic acid, 3 (E)-2-hexadecenoic acids, and 19 sulfates. [ABSTRACT FROM AUTHOR]

When the mass spectra of biological samples (proteins, peptides, and so on) are obtained routinely by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), a serious problem is the reduction of the ionization efficiency by impurities, such as buffer salts and detergents. We focused our attention on devising a method to maintain the ionization efficiency of protein samples, even in the presence of sodium dodecyl sulfate (SDS), without any extra purification step. Although no protein ion peaks are observed in the presence of 2.5% SDS with the usual methods, the addition of a granular anion exchange silica gel to the matrix solution allowed the protein ion peaks to be obtained with an excellent signal-to-noise ratio. Together with other supporting experiments, we suggest that the positively charged surface (the basic environment derived from the anion exchange groups) and the roughness of the particles were important for good ionization in the presence of a high SDS concentration. For a very uneven surface, the SDS might be absorbed into the particle interiors during the process of cocrystallization with the matrix and analytes, which is known as the molecular sieve effect, and the SDS concentration in the surface crystalline film might be reduced. As a result, we developed an on-probe sample preparation method without washes for MALDI, using a strong anion exchange silica gel. This method is applicable even in the presence of 2.5% SDS, and is not only very simple but also inexpensive, because it can be used with the standard MALDI target plates. [ABSTRACT FROM AUTHOR]

Ascidians belonging to the suborder Phlebobranchia are known to accumulate high levels of a transition metal, vanadium, in their blood cells, called vanadocytes, although the mechanism for this biological phenomenon remains unclear. Recently, we identified vanadium(IV)-binding proteins, designated as Vanabins, from vanadium-accumulating ascidians. Here, we report the first 3D structure of Vanabin2 from an ascidian, Ascidia sydneiensis samea, in an aqueous solution. The structure revealed a novel bow- shaped conformation, with four α-helices connected by nine disulfide bonds. There are no structural homologues reported so far. The 15N heteronuclear single-quantum coherence (HSQC) perturbation experiments of Vanabin2 indicated that vanadyl cations, which are exclusively localized on the same face of the molecule, are coordinated by amine nitrogens derived from amino acid residues such as lysines, arginines, and histidines, as suggested by the electron paramagnetic resonance (EPR) results. The present NMR studies provide information that will contribute toward elucidating the mechanism of vanadium accumulation in ascidians. [ABSTRACT FROM AUTHOR]

The first 920 MHz high-resolution NMR (Nuclear Magnetic Resonance) magnet was successfully installed at the Tsukuba Magnet Laboratory of the National Institute for Materials Science. A persistent operation at 21.6 T has continued since April 2002 without any problems. Excellent field stability of 0.31 Hz/h was observed from December 2002 to January 2003. Since July 2002, the magnet was used as an essential part of the only 920 MHz high-resolution NMR spectrometer in the world. The signal-to-noise ratio of 0.1 % ethylbenzene using a proton-selective probe was as high as 2981. An HCN triple-resonance probe is now attached to the spectrometer to contribute to the National Project on Protein Structural and Functional Analysis in Japan. The completion of the second 920 MHz-class NMR spectrometer is scheduled for spring 2004. [ABSTRACT FROM AUTHOR]

Human CA125, encoded by the MUC16 gene, is an ovarian cancer antigen widely used for a serum assay. Its extracellular region consists of tandem repeats of SEA domains. In this study we determined the three-dimensional structure of the SEA domain from the murine MUC16 homologue using multidimensional NMR spectroscopy. The domain forms a unique α/β sandwich fold composed of two α helices and four antiparallel β strands and has a characteristic turn named the TY-turn between α1 and α2. The internal mobility of the main chain is low throughout the domain. The residues that form the hydrophobic core and the TY-turn are fully conserved in all SEA domain sequences, indicating that the fold is common in the family. Interestingly, no other residues are conserved throughout the family. Thus, the sequence alignment of the SEA domain family was refined on the basis of the three-dimensional structure, which allowed us to classify the SEA domains into several subfamilies. The residues on the surface differ between these subfamilies, suggesting that each subfamily has a different function. In the MUC16 SEA domains, the conserved surface residues, Asn-10, Thr-12, Arg-63, Asp75, Asp-112, Ser-115, and Phe-117, are clustered on the β sheet surface, which may be functionally important. The putative epitope (residues 58-77) for anti-MUC16 antibodies is located around the β2 and β3 strands. On the other hand the tissue tumor marker MUC1 has a SEA domain belonging to another subfamily, and its GSVVV motif for proteolytic cleavage is located in the short loop connecting β2 and β3. [ABSTRACT FROM AUTHOR]

Reports on the design of a simple new assay for lipoxygenase inhibitors. Use of the assay to find the novel lipoxygenase inhibitor, tetrapetalone A; Isolation from Streptomyces; Observation that tetrapetalone A has similar inhibitory activity against soybean lipoxygenase to the two well-known lipoxygenase inhibitors, kojic acid and nordihydroguaiareic acid.

Two new bisalkaloids, dipiperamides D and E, were isolated as inhibitors of a drug metabolizing enzyme cytochrome P450 (CYP) 3A4 from the white pepper, Piper nigrum. Their structures were elucidated by spectroscopic methods. Dipiperamides D and E showed potent CYP3A4 inhibition with IC50 values of 0.79 and 0.12 μM, respectively, and other metabolites from the pepper were moderately active or inactive. [Copyright &y& Elsevier]

Abstract: Three new pyrrolobenzodiazepine derivatives, boseongazepines A–C (1–3), were isolated from a culture broth of Streptomyces sp. 11A057, together with the known compound usabamycin B (4). The structures of 1–4 were determined through the analysis of spectroscopic data including extensive 1D-, 2D-NMR, and MS techniques. Cell growth inhibition effects of these compounds were evaluated against Jurkat, K-562, HL-60, and HepG2 cell lines. [Copyright &y& Elsevier]

The article presents a study on the antiproliferative property of 16-O-acetyle-leucotylic acid which acts against human promyelocytic leukemia cells (HL-60). The study examined the separation of the lichen substance from Myelochroa aurulenta and compared the result with the activities of lupanetriterpene, betulin and betulinic acid. Results of the study showed that lichen substance actually had an antiproliferative property which was greater compared to that of betulinic acid.

The chemical structure of tetrapetalone A (1), a novel lipoxygenase inhibitor from Streptomyces sp., was revised by using the 1H–15N HMBC technique. Furthermore, the absolute stereochemistry of all the asymmetric carbons in 1 was determined based on the detailed NOE data of 1 and its derivative. [Copyright &y& Elsevier]

Tetrapetalone A (I), C26H33O7N, is a novel lipoxygenase inhibitor isolated from a culture filtrate of Streptomyces sp. USF-4727 strain. Its chemical structure was determined by its spectroscopic evidence and methylation with diazomethane. The stereochemistry was investigated by the coupling constant in 1H NMR, NOESY data and modified Mosher''s method. I possessed a tetracyclic skeleton and a β-rhodinosyl moiety, and this is the first report of a compound with such a tetracyclic skeleton. [Copyright &y& Elsevier]

A new radical scavenger, thelephorin A, was isolated from the fruiting bodies of the mushroom Thelephora vialis. Its structure was elucidated by spectroscopic methods. Thelephorin A showed antioxidative activity. [Copyright &y& Elsevier]

Many metazoans start germ cell development during embryogenesis, while some metazoans possessing pluripotent stem cells undergo postembryonic germ cell development. The latter reproduce asexually but develop germ cells from pluripotent stem cells or dormant primordial germ cells when they reproduce sexually. Sexual induction of the planarian Dugesia ryukyuensis is an important model for postembryonic germ cell development. In this experimental system, hermaphroditic reproductive organs are differentiated in presumptive gonadal regions by the administration of a crude extract from sexual planarians to asexual ones. However, the substances involved in the first event during postembryonic germ cell development, i.e., ovarian development, remain unknown. Here, we aimed to identify a bioactive compound associated with postembryonic ovarian development. Bioassay-guided fractionation identified ʟ-tryptophan (Trp) on the basis of electrospray ionization-mass spectrometry, circular dichroism, and nuclear magnetic resonance spectroscopy. Originally masked by a large amount of ʟ-Trp, ᴅ-Trp was detected by reverse-phase high-performance liquid chromatography. The ovary-inducing activity of ᴅ-Trp was 500 times more potent than that of ʟ-Trp. This is the first report describing a role for an intrinsic ᴅ-amino acid in postembryonic germ cell development. Our findings provide a novel insight into the mechanisms of germ cell development regulated by low-molecular weight bioactive compounds. [ABSTRACT FROM AUTHOR]

The article presents a study that provides a detailed biosynthetic investigation regarding the use of a marine-derived fungus called Aspergillus sp. in the synthesis of notoamide. Results of the study suggest that the presence of excess 6 in the growth medium changes the metabolite profile of Aspergillus sp. Methods used in the study, as well as the discovery of the marine-derived fungus are also mentioned.

A correction to an article which mentions the notoamide C (3) structure is presented.

A correction to the article "Isolation of Notoamide E, a Key Precursor in the Biosynthesis of Prenylated Indole Alkaloids in a Marine-Derived Fungus, Aspergillus sp.," by Sachiko Tsukamoto, Hikaru Kato, Thomas J. Greshock, Hiroshi Hirota, Tomihisa Ohta, and Robert M. Williams in a 2009 issue is presented.