Iron-sulfur clusters are involved in post-translational arginylation.

Eukaryotic arginylation is an essential post-translational modification that modulates protein stability and regulates protein half-life. Arginylation is catalyzed by a family of enzymes known as the arginyl-tRNA transferases (ATE1s), which are conserved across the eukaryotic domain. Despite their conservation and importance, little is known regarding the structure, mechanism, and regulation of ATE1s. In this work, we show that ATE1s bind a previously undiscovered [Fe-S] cluster that is conserved across evolution. We characterize the nature of this [Fe-S] cluster and find that the presence of the [Fe-S] cluster in ATE1 is linked to its arginylation activity, both in vitro and in vivo, and the initiation of the yeast stress response. Importantly, the ATE1 [Fe-S] cluster is oxygen-sensitive, which could be a molecular mechanism of the N-degron pathway to sense oxidative stress. Taken together, our data provide the framework of a cluster-based paradigm of ATE1 regulatory control.

Efficacy and safety of four COVID-19 vaccines in preventing SARS-CoV-2 infection: A rapid review. / Eficacia y seguridad de cuatro COVID-19 vacunas para prevenir la infección por SARS-CoV-2: una revisión rápida

INTRODUCTION: Since the emergence of the SARS-CoV-2, there have been efforts to develop vaccines to control the COVID-19 pandemic. OBJECTIVE: The present study assessed the efficacy and safety of the BNT162b2, mRNA-1273, ChAdOx1/AZD1222 and Gam-COVID-Vac rAd26-S/rAd5-S vaccines against the SARS-CoV-2. MATERIALS AND METHODS: We searched PubMed/MEDLINE, Google Scholar, Cochrane, and the WHO International Clinical Trials Registry Platform on March 15, 2021. The search terms used were: "vaccine" OR "vaccination" AND "covid19" OR "coronavirus" OR "sarscov2" AND "bnt162b2" OR "chadox1-S" OR "azd1222" OR "sputnik" OR "Gam-COVID-Vac" OR "mrna" OR "mRNA-1273" . We measured the risk of bias of the studies and the quality of the evidence using GRADE profiles. A qualitative and quantitative analysis of the results of clinical trials is presented. RESULTS: Of the 74 identified studies, 4 were finally included in this review. The efficacies of the BNT162b2, mRNA-1273, ChAdOx1/AZD1222 and Gam-COVID-VacrAd26-S/rAd5-S vaccines against symptomatic COVID-19 were 95,0% (CI95% 90,3-97,6), 94,1% (CI95% 89,3-96,8), 66,7% (CI95% 57,4-74,0), and 91,1% (CI95% 83,8-95,1), respectively. There was moderate certainty of the evidence due to serious indirectness, when we measured the risk of bias of the studies and the quality of the evidence using GRADE profile. The safety profiles were acceptable, and data on serious adverse events (summary RR=0,93; CI95% 0,77-1,12; p=0,16) and deaths from all causes (summary RR=0,70; CI95% 0,33-1,50; p=0,90) showed no significant differences. CONCLUSION: The results of this review support the level of evidence for the efficacy and safety of the COVID-19 vaccines analysed.

Introducción. Desde que surgió el virus SARS-CoV-2, se han realizado esfuerzos para desarrollar vacunas para controlar la pandemia por COVID-19. Objetivo. Evaluar los datos de la eficacia y seguridad de las vacunas BNT162b2, mRNA-1273, ChAdOx1/AZD1222 y Gam-COVID-Vac rAd26-S/rAd5-S contra el SARS-CoV-2. Materiales y métodos. Se realizaron búsquedas en PubMed/MEDLINE, Google Scholar, Cochrane y la Plataforma de Registro Internacional de Ensayos Clínicos de la OMS el 15 de marzo de 2021. Los términos usados fueron: "vaccine" OR "vaccination" AND "covid19" OR "coronavirus" OR "sarscov2" AND "bnt162b2" OR "chadox1-S" OR "azd1222" OR "sputnik" OR "Gam-COVID-Vac" OR "mrna" OR "mRNA-1273". Se midió el riesgo de sesgo de los estudios y la calidad de la información por medio de los perfiles GRADE. Se presenta un análisis cualitativo y cuantitativo de los resultados de los estudios clínicos. Resultados. Se identificaron 74 estudios y se incluyeron 4 en la revisión. La eficacia de las vacunas BNT162b2, mRNA-1273, ChAdOx1/AZD1222 y Gam-COVID-VacrAd26-S/rAd5-S contra la COVID-19 sintomática fue del 95,0 % (IC95% 90,3-97,6), 94,1 % (IC95% 89,3-96,8), 66,7 % (IC95% 57,4-74,0) y 91,1 % (IC95% 83,8-95,1), respectivamente, y hubo una certeza moderada de la información debido a la falta de evidencia directa. Los perfiles de seguridad fueron aceptables, y los eventos adversos graves (RR resumido=0,93; IC95% 0,77-1,12; p=0,16) y muerte por todas las causas (RR resumido=0,70; IC95% 0,33-1,50; p=0,90) no mostraron diferencias significativas. Conclusión. Los resultados de esta revisión respaldan el nivel de evidencia de la eficacia y seguridad de las vacunas COVID-19 que fueron analizadas.

Intestinal mucin is a chaperone of multivalent copper.

Mucus protects the epithelial cells of the digestive and respiratory tracts from pathogens and other hazards. Progress in determining the molecular mechanisms of mucus barrier function has been limited by the lack of high-resolution structural information on mucins, the giant, secreted, gel-forming glycoproteins that are the major constituents of mucus. Here, we report how mucin structures we determined enabled the discovery of an unanticipated protective role of mucus: managing the toxic transition metal copper. Using two juxtaposed copper binding sites, one for Cu2+ and the other for Cu1+, the intestinal mucin, MUC2, prevents copper toxicity by blocking futile redox cycling and the squandering of dietary antioxidants, while nevertheless permitting uptake of this important trace metal into cells. These findings emphasize the value of molecular structure in advancing mucosal biology, while introducing mucins, produced in massive quantities to guard extensive mucosal surfaces, as extracellular copper chaperones.

Efficacy and safety of four COVID-19 vaccines in preventing SARS-CoV-2 infection: A rapid review / Eficacia y seguridad de cuatro vacunas COVID-19 para prevenir la infección por SARS-CoV-2: una revisión rápida

Introduction: Since the emergence of the SARS-CoV-2, there have been efforts to develop vaccines to control the COVID-19 pandemic. Objective: The present study assessed the efficacy and safety of the BNT162b2, mRNA-1273, ChAdOx1/AZD1222 and Gam-COVID-Vac rAd26-S/rAd5-S vaccines against the SARS-CoV-2. Materials and methods: We searched PubMed/MEDLINE, Google Scholar, Cochrane, and the WHO International Clinical Trials Registry Platform on March 15, 2021. The search terms used were: "vaccine" OR "vaccination" AND "covid19" OR "coronavirus" OR "sarscov2" AND "bnt162b2" OR "chadox1-S" OR "azd1222" OR "sputnik" OR "Gam-COVID-Vac" OR "mrna" OR "mRNA-1273" . We measured the risk of bias of the studies and the quality of the evidence using GRADE profiles. A qualitative and quantitative analysis of the results of clinical trials is presented. Results: Of the 74 identified studies, 4 were finally included in this review. The efficacies of the BNT162b2, mRNA-1273, ChAdOx1/AZD1222 and Gam-COVID-VacrAd26-S/rAd5-S vaccines against symptomatic COVID-19 were 95,0% (CI95% 90,3-97,6), 94,1% (CI95% 89,3-96,8), 66,7% (CI95% 57,4-74,0), and 91,1% (CI95% 83,8-95,1), respectively. There was moderate certainty of the evidence due to serious indirectness, when we measured the risk of bias of the studies and the quality of the evidence using GRADE profile. The safety profiles were acceptable, and data on serious adverse events (summary RR=0,93; CI95% 0,77-1,12; p=0,16) and deaths from all causes (summary RR=0,70; CI95% 0,33-1,50; p=0°90) showed no significant differences. Conclusion: The results of this review support the level of evidence for the efficacy and safety of the COVID-19 vaccines analysed.

Introducción. Desde que surgió el virus SARS-CoV-2, se han realizado esfuerzos para desarrollar vacunas para controlar la pandemia por COVID-19. Objetivo. Evaluar los datos de la eficacia y seguridad de las vacunas BNT162b2, mRNA-1273, ChAdOx1/AZD1222 y Gam-COVID-Vac rAd26-S/rAd5-S contra el SARS-CoV-2. Materiales y métodos. Se realizaron búsquedas en PubMed/MEDLINE, Google Scholar, Cochrane y la Plataforma de Registro Internacional de Ensayos Clínicos de la OMS el 15 de marzo de 2021. Los términos usados fueron: "vaccine" OR "vaccination" AND "covid19" OR "coronavirus" OR "sarscov2" AND "bnt162b2" OR "chadox1-S" OR "azd1222" OR "sputnik" OR "Gam-COVID-Vac" OR "mrna" OR "mRNA-1273'.' Se midió el riesgo de sesgo de los estudios y la calidad de la información por medio de los perfiles GRADE. Se presenta un análisis cualitativo y cuantitativo de los resultados de los estudios clínicos. Resultados. Se identificaron 74 estudios y se incluyeron 4 en la revisión. La eficacia de las vacunas BNT162b2, mRNA-1273, ChAdOx1/AZD1222 y Gam-COVID-VacrAd26-S/rAd5-S contra la COVID-19 sintomática fue del 95,0 % (IC95% 90,3-97,6), 94,1 % (IC95% 89,3-96,8), 66,7 % (IC95% 57,4-74,0) y 91,1 % (IC95% 83,8-95,1), respectivamente, y hubo una certeza moderada de la información debido a la falta de evidencia directa. Los perfiles de seguridad fueron aceptables, y los eventos adversos graves (RR resumido=0,93; IC95% 0,77-1,12; p=0,16) y muerte por todas las causas (RR resumido=0,70; IC95% 0,33-1,50; p=0,90) no mostraron diferencias significativas. Conclusión. Los resultados de esta revisión respaldan el nivel de evidencia de la eficacia y seguridad de las vacunas COVID-19 que fueron analizadas.

Recommendations for the diagnosis and management of persons with suspected vaccine-induced immune thrombotic thrombocytopenia (VITT) / Recomendaciones para diagnostico y manejo de personas con trombocitopenia trombotica inmune inducida por vacunas (VITT)

Abstract In recent months, rare cases of thrombosis at unusual sites associated with thrombocytopenia, occurring within a typical risk window (i.e., 4-28 days) after receiving SARS CoV2 vaccines, have been reported. Healthcare professionals should be prepared to detect these cases on time. The Expert Panel of the Knowledge Management and Transfer Network conducted a free search of the related literature. With the available information and the clinical expertise of the working group, we formulated, reviewed, and endorsed recommendations for the timely suspicion, diagnosis (case definitions, the use of initial laboratory and imaging tests, specific tests), and management of these thrombotic conditions. This document is considered a living document that will be updated as new evidence emerges, and recommendations may change over time.

Resumen En meses recientes se han reportado casos raros de trombocitopenia y trombosis en sitios inusuales, que ocurren dentro de una ventana de riesgo típica ( por ejemplo de 4 a 28 días) luego de recibir vacunas de SARS CoV 2. Los profesionales de la salud deben estar preparados para detectar estos casos a tiempo. Un panel de expertos y una red de transferencia de conocimiento realizó una búsqueda libre de literatura seleccionada. Con la información disponible y la experticia clínica del grupo de trabajo revisamos y dimos recomendaciones para la sospecha temprana, el diagnostico (definición de caso, el uso de pruebas de laboratorio especificas y de imágenes diagnósticas) para le manejo de estas condiciones tromboticas. Este documento es considerado un documento vivo que debe ser actualizado a medida que surja nueva evidencia y las recomendaciones vayan cambiando con el tiempo

Outpatient Expectant Management of Term Prelabor Rupture of Membranes: A Retrospective Cohort Study.

OBJECTIVE: To examine outcomes among women with prelabor rupture of membranes (PROM) who declined induction and chose outpatient expectant management compared with those admitted for induction. STUDY DESIGN: This is a retrospective cohort study of term women with singleton, vertex-presenting fetuses who presented with PROM between July 2016 and June 2017 and were eligible for outpatient expectant management (n = 166). The primary outcomes were time from PROM to delivery and time from admission to delivery. Maternal and neonatal outcomes were also compared between groups. Multivariable linear regressions were used to assess time differences between groups, adjusting for known maternal and pregnancy characteristics. RESULTS: Compared with admitted patients, women managed expectantly at home had significantly longer PROM to delivery intervals (median 29.2 vs. 17 hours, p < 0.001), but were more likely to deliver within 24 hours of admission (95.1 vs. 82.9%, p = 0.004). In the adjusted analysis, PROM to delivery was 7 hours longer (95% confidence interval [CI]: 3.9-10.0) and admission to delivery was 5.3 hours shorter (95% CI: 2.8-7.7) in the outpatient expectant management cohort. There were no differences in secondary outcomes. CONCLUSION: Outpatient management of term PROM is associated with longer PROM to delivery intervals, but shorter admission to delivery intervals.

Oxytocin Compared to Buccal Misoprostol for Induction of Labor after Term Prelabor Rupture of Membranes.

OBJECTIVE: This study was aimed to determine if admission-to-delivery times vary between term nulliparous women with prelabor rupture of membranes (PROM) who initially receive oxytocin compared with buccal misoprostol for labor induction. STUDY DESIGN: This is a retrospective cohort of 130 term, nulliparous women with PROM and cervical dilation of ≤2 cm who underwent induction of labor with intravenous oxytocin or buccal misoprostol. The primary outcome was time from admission to delivery. Linear regressions with log transformation were used to estimate the effect of induction agent on time to delivery. RESULTS: Women receiving oxytocin had faster admission-to-delivery times than women receiving misoprostol (16.9 vs. 19.9 hours, p = 0.013). There were no significant differences in secondary outcomes between the groups. In the adjusted model, women who received misoprostol had a 22% longer time from admission to delivery (95% CI 5.0-42.0%) compared with women receiving oxytocin. CONCLUSION: In term nulliparous patients with PROM, intravenous oxytocin is associated with faster admission-to-delivery times than buccal misoprostol.

Consenso colombiano de expertos sobre recomendaciones informadas en la evidencia para la prevención, diagnóstico y manejo de la infección por SARS-CoV-2/COVID-19 en paciente pediátrico con enfermedad renal crónica o lesión renal aguda asociada a COVID-19 / Colombian consensus of experts on evidence-informed recommendations for the prevention, diagnosis, and management of SARS-CoV-2 / COVID-19 infection in pediatric patients with chronic kidney disease or acute kidney injury associated with COVID-19

resumen está disponible en el texto completo

Abstract Introduction: The numbers of SARS-CoV-2 infection in the pediatric population are low so far. There is limited information about the behavior of SARS-CoV-2 in a pediatric patient with chronic kidney disease. Objective: To formulate informed recommendations to the prevention, diagnosis, and management of SARS-CoV-2 infection in pediatric patients with kidney disease or acute kidney injury associated with COVID-19 in Colombia. Methodology: A rapid systematic review was performed in Embase and Pubmed databases and scientific societies, to answer questions prioritized by clinical experts in pediatric nephrology. The quality of the evidence was evaluated with validated tools according to the type of study. The preliminary recommendations were consulted by an expert group. The agreement was defined when approval was obtained from at least 70% of the experts consulted. Results: A response was obtained from ' 9 experts in pediatric nephrology in Colombia, who declared the conflict of interest before the consultation. The range of agreement for the recommendations ranged from 78.9% to '00%. The recommendations did not require a second consultation. Conclusion: The evidence-based recommendations for the management of a patient with kidney disease and COVID-19 in the Colombian context are presented.

Consenso colombiano de expertos sobre recomendaciones informadas en la evidencia para la prevención, el diagnóstico y el manejo de la lesión renal aguda por SARS-CoV-2/COVID-19 / Colombian consensus of experts on recommendations informed in the evidence for the prevention, diagnosis and management of acute kidney injury by SARS-CoV-2/COVID-19

resumen está disponible en el texto completo

Abstract Introduction: Acute kidney injury is a frequent complication in patients with COVID-19 and its occurrence is a potential indicator of multi-organ dysfunction and disease severity. Objective: Develop, through an expert consensus, evidence-based recommendations for the prevention, diagnosis, and management of acute kidney injury in patients with SARS CoV2 / COVID-19 infection. Materials and methods: Based on a rapid systematic review in Embase and Pubmed databases and documents from scientific societies, we made preliminary recommendations and consulted with an expert group through an online tool. Then we defined agreement after at least 70 % consensus approval. Quality evidence was evaluated according to the type of document included. The strength of the recommendations was graded as strong or weak. Results: Fifty clinical experts declared their conflict of interest; the consultation took place between May 2 and 29, 2020. The range of agreement ranged from 75.5 % to 100 %. Recommendations for prevention, diagnosis and management of acute kidney injury in patients with SARS CoV2 infection are presented. Conclusions: Although the good quality information available regarding acute kidney injury in patients with COVID-19 is scarce, the recommendations of clinical experts will guide clinical decision-making and strategies around patients with this complication, guaranteeing care focused on the people, with high quality standards, and the generation of safety, health and wellness policies for multidisciplinary care teams.

Consenso colombiano de expertos sobre recomendaciones informadas en la evidencia para la prevención, el diagnóstico y el manejo de la infección por SARS-CoV-2/COVID-19 en pacientes con Enfermedad Renal Crónica en diálisis / Colombian Expert Consensus on Evidence-Informed Recommendations for the Prevention, Diagnosis, and Management of SARS-CoV-2 / COVID-19 Infection in Patients with Chronic Kidney Disease on Dialysis

Resumen Introducción: Las personas con diálisis de mantenimiento se consideran una población en alto riesgo de infección por SARS-CoV-2, complicaciones y muerte. La periodicidad de la diálisis, la organización y la demanda en las unidades de diálisis y las limitaciones de alfabetización en salud poblacional limitan el cumplimiento del aislamiento y el distanciamiento social. Objetivo: Desarrollar, mediante un consenso de expertos, recomendaciones informadas en evidencia para la prevención, el diagnóstico y el manejo de la infección por SARS-CoV-2/COVID-19 en pacientes con enfermedad renal crónica. Materiales y métodos: Se realizó una revisión rápida de literatura en Pubmed, Embase y sociedades científicas. La calidad de evidencia fue evaluada según el tipo de estudio incluido. El acuerdo se definió para cada recomendación con umbral de al menos 70% de aprobación. La fuerza de las recomendaciones fue graduada como fuerte o débil. Resultados: El colectivo fue consultado entre el 17 y 19 de mayo de 2020. Se obtuvo respuesta de 44 expertos clínicos que declararon conflicto de interés previo a la consulta. El acuerdo de las recomendaciones estuvo entre 70,5 y 100%. Se presentan las recomendaciones de un colectivo experto para la prevención, el diagnóstico y el manejo de infección por SARS-CoV-2/COVID-19 en pacientes con enfermedad renal crónica. Conclusión: Debido a la reciente aparición de la infección por SARS-CoV-2 y las incertidumbres respecto a la prevención, el diagnóstico y el manejo, las recomendaciones presentadas se conciben como un estándar colombiano que permita garantizar un cuidado centrado en las personas con enfermedad renal crónica y la protección de los profesionales de la salud.

Abstract Introduction: People with chronic dialysis are considered a population at high risk of SARS CoV2 infection and its derived complications and death. The need to go to strict dialysis schedules, the high demand in the kidney facilities and the difficulties derived from the time and space organization in the rooms in the face to the pandemic added to the difficult learning, teaching and adapting new protocols manifest the needed of standard recommendation according to this problem in people who couldn't have an ideal isolation. Objective: Develop through an expert consensus, evidence-informed recommendations for the prevention, diagnosis, and management of SARS-CoV-2/COVID-19 infection in patients with chronic kidney disease on Dialysis. Materials and methods: We carried out a quick literature review, PubMed, Embase and scientific societies were consulted. The quality of the evidence was considered according to the type of study included. The agreement threshold defined for each recommendation was > 70% approval among experts. The strength of the recommendations was rated as strong or weak. Results: Between May 17 and 19, 2020, was conformed a team of 44 clinical experts who declared their interest conflict prior to the consultation. The agreement of the recommendations was between 70.5% and 100%. The recommendations were separated in prevention, early identification, and diagnostic, isolation in hemodialysis facilities and peritoneal dialysis, and team protection. Ethical considerations also were included. Conclusion: Due to the recent appearance of SARS-CoV-2 infection and the uncertainties regarding prevention, diagnosis and management, the recommendations presented are conceived as a Colombian standard that allows guaranteeing focused care for people with chronic kidney disease and the protection of health team.

Uso de resúmenes de evidencia para informar el tratamiento farmacológico de personas con sospecha o diagnóstico de infección respiratoria por SARS-CoV-2/COVID-19 / Use of evidence summaries to inform pharmacological treatment of people with suspected or diagnosedSARS-CoV-2/COVID-19 respiratory infection

Resumen Introducción: debido a la emergencia del coronavirus SARS-CoV-2 desde diciembre del 2019, se ha generado un gran volumen de producción científica, en algún caso incierta o controvertida especialmente en el manejo farmacológico de los pacientes con esta infección; por lo tanto, se considera relevante buscar alternativas metodológicas para realizar su síntesis rigurosa, sistemática y de calidad, pero con menor tiempo de ejecución y menor costo. Objetivo: presentar la evidencia disponible respecto al manejo farmacológico de personas con sospecha o diagnóstico de infección respiratoria por SARS-CoV-2 (COVID-19) utilizando el método de revisiones sistemáticas rápidas (RS-R) en medicamentos poten- cialmente eficaces para su manejo. Metodología: se realizó una búsqueda sistemática y estructurada en Medline, Embase, Scopus, Cochrane Library, Clinical trials y Google Scholar en inglés. Los estudios incluidos fueron guías de práctica clínica, consensos, revisiones sistemáticas, metaanálisis, ensayos clínicos y otros estudios primarios. La búsqueda y extracción de datos se realizó por múltiples revisores, pero ninguna fue pareada. Resultados: dieciseis preguntas de interés clínico fueron resueltas, relacionadas con el uso en COVID-19 de lopinavir/ ritonavir, nelfinavir, oseltamivir, remdesivir, ribavirina, teicoplanina, umifenovir, favipiravir, tocilizumab, ivermectina y plasma convaleciente; también se evaluó el uso de medicamentos de soporte e incluidos en el manejo como la dexametasona, así como el uso concomitante de medicamentos que generaron dudas como son los AINES, los IECA y los ARA II. Conclusiones: los resúmenes de evidencia se muestran dentro del escenario de la pandemia como una buena alternativa metodológica para ofrecer información de calidad a corto plazo para los tomadores de decisiones.

Abstract Introduction: Due to the emergence of the SARS-CoV-2 coronavirus since December 2019, a large volume of scientific production has been generated, in some cases uncertain or controversial, especially in the pharmacological management of patients with this infection; therefore, it is considered a relevant search for methodological alternatives to carry out its rigorous, systematic and quality synthesis, but with less execution time and lower cost. Objective: To present the available evidence regarding the pharmacological management of people with suspected or diagnosed respiratory SARS-CoV-2 (COVID-19) using the method of rapid systematic reviews (RS-R) in potentially effective drugs for their management. Methodology: A systematic and structured search was conducted in Medline, Embase, Scopus, Cochrane Library, Clinical trials and Google Scholar in English. Studies included clinical practice guidelines, consensus, systematic reviews, meta-analyses, clinical trials, and other primary studies. Data search and extraction were performed by multiple reviewers, but none were paired. Results: Sixteen questions of clinical interest were resolved, related to the use in COVID-19 of lopinavir/ritonavir, nelfinavir, oseltamivir, remdesivir, ribavirin, teicoplanin, umifenovir, favipiravir, tocilizumab, ivermectin, convalescent plasma; the use of support management drugs such as dexamethasone were also evaluated, as well as the concomitant use of drugs that generated doubts, such as NSAIDs, ACEis, and ARA IIs. Conclusions: Summaries of evidence are within the pandemic scenario as a good methodological alternative to offer quality information in the short term for decision-makers.

Structural insights into the mechanism of oxidative activation of heme-free H-NOX from Vibrio cholerae.

Bacterial heme nitric oxide/oxygen (H-NOX) domains are nitric oxide (NO) or oxygen sensors. This activity is mediated through binding of the ligand to a heme cofactor. However, H-NOX from Vibrio cholerae (Vc H-NOX) can be easily purified in a heme-free state that is capable of reversibly responding to oxidation, suggesting a heme-independent function as a redox sensor. This occurs by oxidation of Cys residues at a zinc-binding site conserved in a subset of H-NOX homologs. Remarkably, zinc is not lost from the protein upon oxidation, although its ligation environment is significantly altered. Using a combination of computational and experimental approaches, we have characterized localized structural changes that accompany the formation of specific disulfide bonds between Cys residues upon oxidation. Furthermore, the larger-scale structural changes accompanying oxidation appear to mimic those changes observed upon NO binding to the heme-bound form. Thus, Vc H-NOX and its homologs may act as both redox and NO sensors by completely separate mechanisms.

The FeoC [4Fe-4S] Cluster Is Redox-Active and Rapidly Oxygen-Sensitive.

The acquisition of iron is essential to establishing virulence among most pathogens. Under acidic and/or anaerobic conditions, most bacteria utilize the widely distributed ferrous iron (Fe2+) uptake (Feo) system to import metabolically-required iron. The Feo system is inadequately understood at the atomic, molecular, and mechanistic levels, but we do know it is composed of a main membrane component (FeoB) essential for iron translocation, as well as two small, cytosolic proteins (FeoA and FeoC) hypothesized to function as accessories to this process. FeoC has many hypothetical functions, including that of an iron-responsive transcriptional regulator. Here, we demonstrate for the first time that Escherichia coli FeoC (EcFeoC) binds an [Fe-S] cluster. Using electronic absorption, X-ray absorption, and electron paramagnetic resonance spectroscopies, we extensively characterize the nature of this cluster. Under strictly anaerobic conditions after chemical reconstitution, we demonstrate that EcFeoC binds a redox-active [4Fe-4S]2+/+ cluster that is rapidly oxygen-sensitive and decays to a [2Fe-2S]2+ cluster (t1/2 ≈ 20 s), similar to the [Fe-S] cluster in the fumarate and nitrate reductase (FNR) transcriptional regulator. We further show that this behavior is nearly identical to the homologous K. pneumoniae FeoC, suggesting a redox-active, oxygen-sensitive [4Fe-4S]2+ cofactor is a general phenomenon of cluster-binding FeoCs. Finally, in contrast to FNR, we show that the [4Fe-4S]2+ cluster binding to FeoC is associated with modest conformational changes of the polypeptide, but not protein dimerization. We thus posit a working hypothesis in which the cluster-binding FeoCs may function as oxygen-sensitive iron sensors that fine-tune pathogenic ferrous iron acquisition.

pH-Induced Binding of the Axial Ligand in an Engineered CuA Site Favors the πu State.

CuA centers perform efficient long-range electron transfer. The electronic structure of native CuA sites can be described by a double-potential well with a dominant σu* ground state in fast equilibrium with a less populated πu ground state. Here, we report a CuA mutant in which a lysine was introduced in the axial position. This results in a highly unstable protein with a pH-dependent population of the two ground states. Deep analysis of the high-pH form of this variant shows the stabilization of the πu ground state due to direct binding of the Lys residue to the copper center that we attribute to deprotonation of this residue.

Crystal structures of AztD provide mechanistic insights into direct zinc transfer between proteins.

Zinc acquisition from limited environments is critical for bacterial survival and pathogenesis. AztD has been identified as a periplasmic or cell surface zinc-binding protein in numerous bacterial species. In Paracoccus denitrificans, AztD can transfer zinc directly to AztC, the solute binding protein for a zinc-specific ATP-binding cassette transporter system, suggesting a role in zinc acquisition and homeostasis. Here, we present the first cry stal structures of AztD from P. denitrificans and tbe human pathogen Citrobacter koseri, revealing a beta-propeller fold and two high-affinity zinc-binding sites that are highly conserved among AztD homologs. These structures combined with transfer assays using WT and mutant proteins provide rare insight into the mechanism of direct zinc transfer from one protein to another. Given the importance of zinc import to bacterial pathogenesis, these insights may prove valuable to the development of zinc transfer inhibitors as antibiotics.

Factores de riesgo y enfermedades cardiometabólicas en Risaralda 2017 proyectada a 2050 / Risk factors and cardiometabolic disease in Risaralda 2017 to 2050

Resumen Objetivo: Proyectar el comportamiento de factores de riesgo y de la incidencia de dos enfermedades cardiometabólicas, en una población colombiana entre 2017 y 2050. Metodología: Diseño de cohorte abierta basado en un modelo de microsimulación dinámica para la población adulta de Risaralda, Colombia. Los factores de riesgo analizados son tabaquismo, obesidad global, obesidad central y colesterol total. Se creó una población sintética que replica las características demográficas y de salud de Risaralda en 2010, utilizando algoritmos de emparejamiento e imputación estadística. La evolución a lo largo del curso de vida se simuló basada en reglas derivadas de la literatura, con ecuaciones estocásticas y modelos econométricos. Se calcula la incidencia de diabetes tipo II y de eventos cerebrovasculares isquémicos de 2017 a 2050. Resultados: En 2050, 16.7 % serán fumadores, la tercera parte de ellos presentarán obesidad global y más de la mitad presentarán obesidad central. El promedio de colesterol total aumentará 5 mg/dL. Adicionalmente, se espera que entre 2017 y 2050 se presenten 204.966 casos nuevos de diabetes y 65.758 eventos cerebrovasculares isquémicos. Conclusiones: Los estilos de vida y el envejecimiento poblacional, llevarán a mayor exposición a riesgo y aumentarán la velocidad a la que los risaraldenses se enfermarán de Diabetes y experimentarán eventos cerebrovasculares. La obesidad global y central son factores que explicarían esta tendencia. Se requieren intervenciones intersectoriales que protejan a la población y reduzcan cargas fiscales por condiciones evitables.

Abstract Objective: predict the behavior of the risk factors and the incidence of two cardiometabolic diseases in a population from Colombia between 2017 and 2050. Methodology: Follow up of individual's cohort of an artificial society of Risaralda, Colombia, based on a microsimulation model. The risk factors analyzed in this study are tobacco use, obesity, central obesity and total cholesterol. A synthetic population was created to replicate demographic and health characteristics of Risaralda in 2010, using pairing algorithms and statistical imputation. The evolution along the life course was simulated based on rules from scientific literature, with stochastic equations and econometric estimates. The incidence of type II diabetes and ischemic stroke is calculated for the adult population between 2017 to 2050. Results: 16.7% of the adults by 2050 is expected to be smokers, a third of them will have global obesity and more than half will have central obesity. The average level of serum total cholesterol would increase by 5 mg/dL. Additionally, is expected that between 2017 and 2050 there will be 204.966 incident cases of diabetes and 65.758 first-ever ischemic stroke events. Conclusions: Lifestyles and expected population aging will lead to greater risk of disease and will increase the rate at which local people will get diabetes and ischemic stroke. Risk factors like global and central obesity explain this trend. Effective intersectoral interventions are needed to protect the population and reduce tax burden due to preventable conditions.

Trapping intermediates in metal transfer reactions of the CusCBAF export pump of Escherichia coli.

Escherichia coli CusCBAF represents an important class of bacterial efflux pump exhibiting selectivity towards Cu(I) and Ag(I). The complex is comprised of three proteins: the CusA transmembrane pump, the CusB soluble adaptor protein, and the CusC outer-membrane pore, and additionally requires the periplasmic metallochaperone CusF. Here we used spectroscopic and kinetic tools to probe the mechanism of copper transfer between CusF and CusB using selenomethionine labeling of the metal-binding Met residues coupled to RFQ-XAS at the Se and Cu edges. The results indicate fast formation of a protein-protein complex followed by slower intra-complex metal transfer. An intermediate coordinated by ligands from each protein forms in 100 ms. Stopped-flow fluorescence of the capping CusF-W44 tryptophan that is quenched by metal transfer also supports this mechanism. The rate constants validate a process in which shared-ligand complex formation assists protein association, providing a driving force that raises the rate into the diffusion-limited regime.

Effect of circular permutation on the structure and function of type 1 blue copper center in azurin.

Type 1 copper (T1Cu) proteins are electron transfer (ET) proteins involved in many important biological processes. While the effects of changing primary and secondary coordination spheres in the T1Cu ET function have been extensively studied, few report has explored the effect of the overall protein structural perturbation on active site configuration or reduction potential of the protein, even though the protein scaffold has been proposed to play a critical role in enforcing the entatic or "rack-induced" state for ET functions. We herein report circular permutation of azurin by linking the N- and C-termini and creating new termini in the loops between 1st and 2nd ß strands or between 3rd and 4th ß strands. Characterization by electronic absorption, electron paramagnetic spectroscopies, as well as crystallography and cyclic voltammetry revealed that, while the overall structure and the primary coordination sphere of the circular permutated azurins remain the same as those of native azurin, their reduction potentials increased by 18 and 124 mV over that of WTAz. Such increases in reduction potentials can be attributed to subtle differences in the hydrogen-bonding network in secondary coordination sphere around the T1Cu center.

Kß Valence to Core X-ray Emission Studies of Cu(I) Binding Proteins with Mixed Methionine - Histidine Coordination. Relevance to the Reactivity of the M- and H-sites of Peptidylglycine Monooxygenase.

Biological systems use copper as a redox center in many metalloproteins, where the role of the metal is to cycle between its +1 and +2 oxidation states. This chemistry requires the redox potential to be in a range that can stabilize both Cu(I) and Cu(II) states and often involves protein-derived ligand sets involving mixed histidine-methionine coordination that balance the preferences of both oxidation states. Transport proteins, on the other hand, utilize copper in the Cu(I) state and often contain sites comprised predominately of the cuprophilic residue methionine. The electronic factors that allow enzymes and transporters to balance their redox requirements are complex and are often elusive due to the dearth of spectroscopic probes of the Cu(I) state. Here we present the novel application of X-ray emission spectroscopy to copper proteins via a study of a series of mixed His-Met copper sites where the ligand set varies in a systematic way between the His3 and Met3 limits. The sites are derived from the wild-type peptidylglycine monooxygenase (PHM), two single-site variants which replicate each of its two copper sites (CuM-site and CuH-site), and the transporters CusF and CusB. Clear differences are observed in the Kß2,5 region at the Met3 and His3 limits. CusB (Met3) has a distinct peak at 8978.4 eV with a broad shoulder at 8975.6 eV, whereas CuH (His3) has two well-resolved features: a more intense feature at 8974.8 eV and a second at 8977.2 eV. The mixed coordination sphere CusF (Met2His) and the PHM CuM variant (Met1His2) have very similar spectra consisting of two features at 8975.2 and 8977.8 eV. An analysis of DFT calculated spectra indicate that the intensity of the higher energy peak near 8978 eV is mediated by mixing of ligand-based orbitals into the Cu d(10) manifold, with S from Met providing more intensity by facilitating increased Cu p-d mixing. Furthermore, reaction of WT PHM with CO (an oxygen analogue) produced the M site CO complex, which showed a unique XES spectrum that could be computationally reproduced by including interactions between Cu(I) and the CO ligand. The study suggests that the valence-to-core (VtC) region can not only serve as a probe of ligand speciation but also offer insight into the coordination geometry, in a fashion similar to XAS pre-edges, and may be sufficiently sensitive to the coordination of exogenous ligands to be useful in the study of reaction mechanisms.

Design of a single protein that spans the entire 2-V range of physiological redox potentials.

The reduction potential (E°') is a critical parameter in determining the efficiency of most biological and chemical reactions. Biology employs three classes of metalloproteins to cover the majority of the 2-V range of physiological E°'s. An ultimate test of our understanding of E°' is to find out the minimal number of proteins and their variants that can cover this entire range and the structural features responsible for the extreme E°'. We report herein the design of the protein azurin to cover a range from +970 mV to -954 mV vs. standard hydrogen electrode (SHE) by mutating only five residues and using two metal ions. Spectroscopic methods have revealed geometric parameters important for the high E°'. The knowledge gained and the resulting water-soluble redox agents with predictable E°'s, in the same scaffold with the same surface properties, will find wide applications in chemical, biochemical, biophysical, and biotechnological fields.