Structure and electron-transfer pathway of the human methionine sulfoxide reductase MsrB3

Introduction: The post-translational oxidation of methionine to methionine sulfoxide is a reversible process, enabling repair of oxidative damage to proteins and the use of sulfoxidation as a regulatory switch. Methionine sulfoxide reductases catalyze the stereospecific reduction of methionine sulfoxide. One of the mammalian methionine sulfoxide reductases, MsrB3, has a signal sequence for entry into the endoplasmic reticulum (ER). In the ER, MsrB3 is expected to encounter a distinct redox environment compared to its paralogs in the cytosol, nucleus, and mitochondria. Aims: We sought to determine the location and arrangement of MsrB3 redox-active cysteines, which may couple MsrB3 activity to other redox events in the ER. Results: We determined the human MsrB3 structure using X-ray crystallography. The structure revealed that a disulfide bond near the protein amino terminus is distant in space from the active site. Nevertheless, biochemical assays showed that these amino-terminal cysteines are oxidized by the MsrB3 active site after its reaction with methionine sulfoxide. Innovation: This study reveals a mechanism to shuttle oxidizing equivalents from the primary MsrB3 active site toward the enzyme surface, where they would be available for further dithiol-disulfide exchange reactions. Conclusion: Conformational changes must occur during the MsrB3 catalytic cycle to transfer oxidizing equivalents from the active site to the amino-terminal redox-active disulfide. The accessibility of this exposed disulfide may help couple MsrB3 activity to other dithiol/disulfide redox events in the secretory pathway

No evidence for association between polymorphisms in GRM3 and schizophrenia

BACKGROUND: Three studies have previously reported data that were interpreted by the authors as supportive of association between schizophrenia and polymorphisms in the gene encoding the metabotropic glutamate receptor GRM3. METHODS: In a bid to examine this hypothesis, we examined seven SNPs spanning GRM3 in a UK case-control sample (schizophrenic cases n = 674, controls n = 716). These included all SNPs previously reported to be associated, alone or in haplotypes, with schizophrenia in European or European American samples. RESULTS: Our data showed no evidence for association with single markers, or 2, 3, 4 and 5 marker haplotypes, nor did any specific haplotypes show evidence for association according to previously observed patterns. CONCLUSION: Examination of our own data and those of other groups leads us to conclude that at present, GRM3 should not be viewed as a gene for which there is replicated evidence for association with schizophrenia

Sistema de monitoreo remoto con detección de movimiento basado en visión por computadora

En este trabajo se presenta un sistema de monitoreo remoto con detección de movimiento basado en visión por computadora. El sistema está compuesto por una cámara web con conexión USB montada en una plataforma de dos servomotores para controlar el giro horizontal y vertical. El algoritmo de visión artificial fue implementado utilizando el ambiente gráfico de LabVIEW y el Toolkit Vision Aquisition. Además, se utilizó un microcontrolador Arduino Uno para controlar el movimiento de los servomotores. El algoritmo es capaz de detectar movimiento en un ambiente cerrado y con iluminación controlada mediante sustracción de imágenes consecutivas y comparación con un factor de sensibilidad. La utilización de LabVIEW como ambiente de programación permite la modularización del algoritmo, una implementación simple y una interfaz atractiva para el usuario donde se pueden hacer modificaciones con facilidad. Finalmente se utilizó la herramienta de publicación Web de LabVIEW para subir la aplicación en un servidor y acceder a ella de forma remota desde una computadora personal a distancia o dispositivos móviles como teléfonos inteligentes y tabletas

Optimizing antibody affinity and stability by the automated design of the variable light-heavy chain interfaces.

Antibodies developed for research and clinical applications may exhibit suboptimal stability, expressibility, or affinity. Existing optimization strategies focus on surface mutations, whereas natural affinity maturation also introduces mutations in the antibody core, simultaneously improving stability and affinity. To systematically map the mutational tolerance of an antibody variable fragment (Fv), we performed yeast display and applied deep mutational scanning to an anti-lysozyme antibody and found that many of the affinity-enhancing mutations clustered at the variable light-heavy chain interface, within the antibody core. Rosetta design combined enhancing mutations, yielding a variant with tenfold higher affinity and substantially improved stability. To make this approach broadly accessible, we developed AbLIFT, an automated web server that designs multipoint core mutations to improve contacts between specific Fv light and heavy chains (http://AbLIFT.weizmann.ac.il). We applied AbLIFT to two unrelated antibodies targeting the human antigens VEGF and QSOX1. Strikingly, the designs improved stability, affinity, and expression yields. The results provide proof-of-principle for bypassing laborious cycles of antibody engineering through automated computational affinity and stability design