4I5Q image
Deposition Date 2012-11-28
Release Date 2013-10-16
Last Version Date 2024-11-13
Entry Detail
PDB ID:
4I5Q
Keywords:
Title:
Crystal structure and catalytic mechanism for peroplasmic disulfide-bond isomerase DsbC from Salmonella enterica serovar Typhimurium
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
1.96 Å
R-Value Free:
0.25
R-Value Work:
0.20
R-Value Observed:
0.20
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Thiol:disulfide interchange protein DsbC
Gene (Uniprot):dsbC
Chain IDs:A, B
Chain Length:222
Number of Molecules:2
Biological Source:Salmonella typhimurium
Ligand Molecules
Primary Citation
Crystal structure of the periplasmic disulfide-bond isomerase DsbC from Salmonella enterica serovar Typhimurium and the mechanistic implications.
J.Struct.Biol. 183 1 10 (2013)
PMID: 23726983 DOI: 10.1016/j.jsb.2013.05.013

Abstact

The 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.

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Primary Citation of related structures