4i5q
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Crystal structure and catalytic mechanism for peroplasmic disulfide-bond isomerase DsbC from Salmonella enterica serovar Typhimurium
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Structural highlights
FunctionDSBC_SALTY Required for disulfide bond formation in some periplasmic proteins. Acts by transferring its disulfide bond to other proteins and is reduced in the process. DsbC is reoxidized by a yet uncharacterized protein. Also acts as a disulfide isomerase. Publication Abstract from PubMedThe disulfide-bond isomerase DsbC plays a crucial role in the folding of bacterial proteins in the periplasmic space. DsbC has a V-shaped dimeric structure with two domains, and Cys98 in the C-terminal domain attacks inappropriate disulfide bonds in substrate proteins due to its high nucleophilic activity. In this article, we present the crystal structure of DsbC from Salmonella enterica serovar Typhimurium. We evaluated the conserved residues Asp95 and Arg125, which are located close to Cys98. The mutation of Asp95 or Arg125 abolished the disulfide isomerase activity of DsbC in an in vitro assay using a protein substrate, and the R125A mutation significantly reduced the chaperone activity for the substrate RNase I in vivo. Furthermore, a comparative analysis suggested that the conformation of Arg125 varies depending on the packing or protein-protein interactions. Based on these findings, we suggest that Asp95 and Arg125 modulate the pKa of Cys98 during catalysis. Crystal structure of the periplasmic disulfide-bond isomerase DsbC from Salmonella enterica serovar Typhimurium and the mechanistic implications.,Jiao L, Kim JS, Song WS, Yoon BY, Lee K, Ha NC J Struct Biol. 2013 Jul;183(1):1-10. doi: 10.1016/j.jsb.2013.05.013. Epub 2013, May 29. PMID:23726983[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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This page was last modified 08:43, 9 November 2022.