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Distinguishing proton-coupled electron transfer (PCET) from uncoupled electron transfer (ET) in proteins can be challenging. A recent investigation [J. C. Koone, M. Simmang, D. L. Saenger, M. L. Hunsicker-Wang and B. F. Shaw, J. Am. Chem. Soc., 145, 16488–16497] reported that protein charge ladders and capillary electrophoresis can distinguish between single ET, PCET, and two-proton coupled ET (2PCET) by directly measuring the change in protein net charge upon reduction/oxidation (ΔZET). The current study used similar methods to assess PCET in zinc-free, "double copper" superoxide dismutase-1 (4Cu-SOD1), where one copper is bound at the copper site of each monomer and one copper is bound at the bridging zinc site, resulting in a quasi-type III Cu center. At pH 7.4, the net charge (Z) of the 4Cu-SOD1 dimer was unaffected by reduction of all four Cu2+ ions, i.e., ΔZ4ET = −0.09 ± 0.05 per dimer (−0.02 ± 0.01 per copper atom). These values suggest that PCET is taking place at all four Cu atoms of the homodimer. Molecular dynamics and Poisson–Boltzmann calculations suggest that a metal-coordinating histidine at the zinc site (His71) is the proton acceptor. These data show how ligands of a naturally occurring zinc site can help facilitate PCET when the right redox metal is bound. [ABSTRACT FROM AUTHOR]

The de novo design of miniprotein inhibitors has recently emerged as a new technology to create proteins that bind with high affinity to specific therapeutic targets. Their size, ease of expression, and apparent high stability makes them excellent candidates for a new class of protein drugs. However, beyond circular dichroism melts and hydrogen/deuterium exchange experiments, little is known about their dynamics, especially at the elevated temperatures they seemingly tolerate quite well. To address that and gain insight for future designs, we have focused on identifying unintended and previously overlooked heat‐induced structural and chemical changes in a particularly stable model miniprotein, EHEE_rd2_0005. Nuclear magnetic resonance (NMR) studies suggest the presence of dynamics on multiple time and temperature scales. Transiently elevating the temperature results in spontaneous chemical deamidation visible in the NMR spectra, which we validate using both capillary electrophoresis and mass spectrometry (MS) experiments. High temperatures also result in greatly accelerated intrinsic rates of hydrogen exchange and signal loss in NMR heteronuclear single quantum coherence spectra from local unfolding. These losses are in excellent agreement with both room temperature hydrogen exchange experiments and hydrogen bond disruption in replica exchange molecular dynamics simulations. Our analysis reveals important principles for future miniprotein designs and the potential for high stability to result in long‐lived alternate conformational states. [ABSTRACT FROM AUTHOR]

The functional and structural significance of the intrasubunit disulfide bond in copper-zinc superoxide dismutase (SOD1) was studied by characterizing mutant forms of human SOD1 (hSOD) and yeast SOD1 lacking the disulfide bond. We determined x-ray crystal structures of metal-bound and metal-deficient hC57S SOD1. C57S hSOD1 isolated from yeast contained four zinc ions per protein dimer and was structurally very similar to wild type. The addition of copper to this four-zinc protein gave properly reconstituted 2Cu,2Zn C57S hSOD, and its spectroscopic properties indicated that the coordination geometry of the copper was remarkably similar to that of holo wild type hSOD1. In contrast, the addition of copper and zinc ions to apo C57S human SOD1 failed to give proper reconstitution. Using pulse radiolysis, we determined SOD activities of yeast and human SOD1s lacking disulfide bonds and found that they were enzymatically active at ∼10% of the wild type rate. These results are contrary to earlier reports that the intrasubunit disulfide bonds in SOD1 are essential for SOD activity. Kinetic studies revealed further that the yeast mutant SOD1 had less ionic attraction for superoxide, possibly explaining the lower rates. Saccharomyces cerevisiae cells lacking the sod1 gene do not grow aerobically in the absence of lysine, but expression of C57S SOD1 increased growth to 30-50% of the growth of cells expressing wild type SOD1, supporting that C57S SOD1 retained a significant amount of activity.

Mutations in the gene encoding Cu-Zn superoxide dismutase (SOD1) are one of the causes of familial amyotrophic lateral sclerosis (FALS). Fibrillar inclusions containing SOD1 and SOD1 inclusions that bind the amyloid-specific dye thioflavin S have been found in neurons of transgenic mice expressing mutant SOD1. Therefore, the formation of amyloid fibrils from human SOD1 was investigated. When agitated at acidic pH in the presence of low concentrations of guanidine or acetonitrile, metalated SOD1 formed fibrillar material which bound both thioflavin T and Congo red and had circular dichroism and infrared spectra characteristic of amyloid. While metalated SOD1 did not form amyloid-like aggregates at neutral pH, either removing metals from SOD1 with its intramolecular disulfide bond intact or reducing the intramolecular disulfide bond of metalated SOD1 was sufficient to promote formation of these aggregates. SOD1 formed amyloid-like aggregates both with and without intermolecular disulfide bonds, depending on the incubation conditions, and a mutant SOD1 lacking free sulfhydryl groups (AS-SOD1) formed amyloid-like aggregates at neutral pH under reducing conditions. ALS mutations enhanced the ability of disulfide-reduced SOD1 to form amyloid-like aggregates, and apo-AS-SOD1 formed amyloid-like aggregates at pH 7 only when an ALS mutation was also present. These results indicate that some mutations related to ALS promote formation of amyloid-like aggregates by facilitating the loss of metals and/or by making the intramolecular disulfide bond more susceptible to reduction, thus allowing the conversion of SOD1 to a form that aggregates to form resembling amyloid. Furthermore, the occurrence of amyloid-like aggregates per se does not depend on forming intermolecular disulfide bonds, and multiple forms of such aggregates can be produced from SOD1.

Mutations in the gene encoding Cu-Zn superoxide dismutase (SOD1) are one of the causes of familial amyotrophic lateral sclerosis (FALS). Fibrillar inclusions containing SOD1 and SOD1 inclusions that bind the amyloid-specific dye thioflavin S have been found in neurons of transgenic mice expressing mutant SOD1. Therefore, the formation of amyloid fibrils from human SOD1 was investigated. When agitated at acidic pH in the presence of low concentrations of guanidine or acetonitrile, metalated SOD1 formed fibrillar material which bound both thioflavin T and Congo red and had circular dichroism and infrared spectra characteristic of amyloid. While metalated SOD1 did not form amyloid-like aggregates at neutral pH, either removing metals from SOD1 with its intramolecular disulfide bond intact or reducing the intramolecular disulfide bond of metalated SOD1 was sufficient to promote formation of these aggregates. SOD1 formed amyloid-like aggregates both with and without intermolecular disulfide bonds, depending on the incubation conditions, and a mutant SOD1 lacking free sulfhydryl groups (AS-SOD1) formed amyloid-like aggregates at neutral pH under reducing conditions. ALS mutations enhanced the ability of disulfide-reduced SOD1 to form amyloid-like aggregates, and apo-AS-SOD1 formed amyloid-like aggregates at pH 7 only when an ALS mutation was also present. These results indicate that some mutations related to ALS promote formation of amyloid-like aggregates by facilitating the loss of metals and/or by making the intramolecular disulfide bond more susceptible to reduction, thus allowing the conversion of SOD1 to a form that aggregates to form resembling amyloid. Furthermore, the occurrence of amyloid-like aggregates per se does not depend on forming intermolecular disulfide bonds, and multiple forms of such aggregates can be produced from SOD1.

Programs aiming to reduce intimate partner violence (IPV) increasingly seek to shift social norms. Few interventions have been rigorously evaluated for their impact on norms and incidence of IPV, particularly in sub-Saharan Africa. Shifting norms at the community level and subsequent pathways to behavior change remain poorly understood. We assessed shifts in individual- and couple-level factors, social norms, and IPV from an 18-month community-based trial of the Masculinity, Faith, and Peace (MFP) program—a faith-based, norms-shifting approach—in Plateau state, Nigeria. This study was part of a community-based, mixed-methods, two-arm cluster randomized control trial (cRCT) to evaluate the MFP program. Quantitative surveys were conducted with women 18 to 35 years old (n = 350) and their male partners (n = 281). Respondents came from 10 Muslim and 10 Christian congregations. Social norms were measured based on results from factor analysis. Intent-to-treat analyses assessed intervention effects. Qualitative research in MFP congregations explored pathways of change. All forms of IPV reduced over time among MFP participants. Regression analyses showed a significant 61% reduction in odds of reporting experiencing any IPV among women, a 64% reduction among Christians, and a 44% reduction in MFP congregations compared to their respective controls. In addition to improvement in norms, we found significant intervention effects on individual attitudes toward IPV and gender roles, relationship quality, and community cohesion. Qualitative findings reinforce these pathways, suggesting that critical reflection and dialogue on existing norms and the focus on faith and religious texts were valued by participants and supported IPV reductions. This study demonstrates that a faith-based, norms-shifting intervention can significantly reduce IPV in a short time. There are several pathways through which MFP reduced IPV, including shifts in norms, attitudes, relationship quality, and community cohesion. [ABSTRACT FROM AUTHOR]

Northeast Colorado's livestock operations have been identified as a major contributor to reactive nitrogen deposition in the Rocky Mountains National Park (RMNP). We present a review on the state of knowledge concerning the emission, transport, deposition, and mitigation of gaseous ammonia (NH3) from open-lot cattle feeding facilities located east of the Northern Front Range of the Rocky Mountains. Gaseous NH3 mitigation strategies discussed are related to diet manipulation and management practices. Crude protein content of 11% and condensed tannins of 8% reduced the NH3 emission by 43% and 57%, respectively. Ambiguous results for NH3 mitigation by using water sprinklers have been reported—an increase in NH3 emission by 27% and decrease of 27 to 56%. Manure harvesting should be evaluated in terms of maintaining proper moisture content, and not necessarily as a mitigation option. The use of chemical and physical manure amendments has shown a wide range in NH3 mitigation effectiveness, ranging from 19 to 98% for chemical and 0 to 43% for physical amendments, respectively. The review outlined the scientific basis, practicality, and expected efficacy of each management practice. The most plausible management practices to reduce NH3 emissions from corral surfaces in cattle feedyards are presented. [ABSTRACT FROM AUTHOR]

ABSTRACT As of December 2006, the American Meteorological Society/U.S. Environmental Protection Agency (EPA) Regulatory Model with Plume Rise Model Enhancements (AER-MOD-PRIME; hereafter AERMOD) replaced the Industrial Source Complex Short Term [...]

The studies of mesoscopic inhomogeneity of conducting polymers using scanning probe techniques such as Kelvin probe force microscopy (KFM) and current-sensing atomic force microscopy (CS-AFM) are presented.

More than 100 different mutations in the gene encoding copper-zinc superoxide dismutase (SOD1) cause familial forms of amyotrophic lateral sclerosis (ALS)--a fatal neurodegenerative disease in which aggregation of the SOD1 protein is considered to be the primary mode of pathogenesis. Recent results show that these mutations have remarkably diverse and unexpected effects on the structure, activity and native state stability of SOD1. Intriguingly, many mutations seem to have no measurable effect on the biophysical and biochemical properties of SOD1, except for decreasing the net charge of the protein. Thus, it seems likely that different ALS-associated mutations promote SOD1 aggregation by fundamentally distinct mechanisms. Understanding this complexity has implications for drug development and treatment of the disease.

ABSTRACT Controlled bench-scale laboratory experiments were conducted to evaluate the recovery of ammonia (N[H.sub.3]) and hydrogen sulfide ([H.sub.2]S) from dynamic isolation flux chambers. [H.sub.2]S (80-4000 ppb) and N[H.sub.3] (5000-40,000 ppb) [...]

Background: Many patients with a self-reported penicillin allergy go on to tolerate beta-lactam antibiotics. Allergy specialists may be consulted to determine the nature and extent of the allergy. However, electronic allergy records must be appropriately updated such that recommendations are carried forward. Objective: To determine the percentage of patients who have their electronic allergy record updated after an allergy service consult (ASC). Methods: This was a retrospective study of patients with at least 1 documented beta-lactam allergy and had an ASC during (inpatient) or prior to (outpatient) hospital admission at Northwestern Memorial Hospital and Prentice Women's Hospital in Chicago, Illinois. Results: Within the study period, a total of 26 526 patients were identified as having a documented antibiotic allergy, with 21 657 patients (81.6% of patients with allergies) having a listed beta-lactam allergy. Of these patients, 1689 (7.8%) patients were identified as having an ASC during or prior to admission, with 598 patients meeting inclusion criteria. Changes in the allergy record were recommended by the ASC for 62% (n = 371) of patients; however, the allergy record was updated after the ASC in 74.9% (n = 278) of patients. Conclusion: ASC recommendations to delabel a patient as beta-lactam allergic must result in updating the allergy record in order to optimize future treatment. Given the low proportion of allergy-labeled patients tested, programs outside formal ASCs should be considered. [ABSTRACT FROM AUTHOR]

Brian J. Shaw, Davidson College Two decades ago Perry Anderson (Considerations on Western Marxism, 1976) argued that the triple catastrophe of Stalinism, Nazism, and Keynesianism had prompted the fatal retreat [...]