Structural and Functional Characterization of Three DsbA Paralogues from Salmonella enterica Serovar Typhimurium |
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Authors: | Bego?a Heras Makrina Totsika Russell Jarrott Stephen R Shouldice Gregor Gun?ar Maud E S Achard Timothy J Wells M Pilar Argente Alastair G McEwan Mark A Schembri |
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Institution: | From the ‡Institute for Molecular Bioscience and ;§School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane QLD 4072, Australia and ;the ¶Jožef Stefan Institute, Ljubljana 1000, Slovenia |
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Abstract: | In prototypic Escherichia coli K-12 the introduction of disulfide bonds into folding proteins is mediated by the Dsb family of enzymes, primarily through the actions of the highly oxidizing protein EcDsbA. Homologues of the Dsb catalysts are found in most bacteria. Interestingly, pathogens have developed distinct Dsb machineries that play a pivotal role in the biogenesis of virulence factors, hence contributing to their pathogenicity. Salmonella enterica serovar (sv.) Typhimurium encodes an extended number of sulfhydryl oxidases, namely SeDsbA, SeDsbL, and SeSrgA. Here we report a comprehensive analysis of the sv. Typhimurium thiol oxidative system through the structural and functional characterization of the three Salmonella DsbA paralogues. The three proteins share low sequence identity, which results in several unique three-dimensional characteristics, principally in areas involved in substrate binding and disulfide catalysis. Furthermore, the Salmonella DsbA-like proteins also have different redox properties. Whereas functional characterization revealed some degree of redundancy, the properties of SeDsbA, SeDsbL, and SeSrgA and their expression pattern in sv. Typhimurium indicate a diverse role for these enzymes in virulence. |
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Keywords: | Bacterial Toxins Disulfide Enzyme Mechanisms Protein Folding Protein Structure Bacterial Virulence Disulfide Catalysis Dsb Proteins Redox Homeostasis |
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