PDBsum entry 4i5q

Isomerase

PDB id: 4i5q

Contents

Protein chains

220 a.a.

Metals

_MG

Waters ×348

PDB id:

4i5q

Name:

Isomerase

Title:

Crystal structure and catalytic mechanism for peroplasmic disulfide- bond isomerase dsbc from salmonella enterica serovar typhimurium

Structure:

Thiol:disulfide interchange protein dsbc. Chain: a, b. Engineered: yes

Source:

Salmonella typhimurium. Organism_taxid: 99287. Strain: lt2 / sgsc1412 / atcc 700720. Gene: dsbc, stm3043. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

1.96Å R-factor: 0.206 R-free: 0.254

Authors:

N.C.Ha,J.Li,J.S.Kim,B.Y.Yoon,J.H.Yeom,K.Lee

Key ref:

L.Jiao et al. (2013). Crystal structure of the periplasmic disulfide-bond isomerase DsbC from Salmonella enterica serovar Typhimurium and the mechanistic implications. J Struct Biol, 183, 1. PubMed id: 23726983 DOI: 10.1016/j.jsb.2013.05.013

Date:

28-Nov-12 Release date: 16-Oct-13

Protein chains

P55890  (DSBC_SALTY) -  Thiol:disulfide interchange protein DsbC from Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720)

Seq: 237 a.a.

Struc: 220 a.a.*

* PDB and UniProt seqs differ at 7 residue positions (black crosses)

DOI no: 10.1016/j.jsb.2013.05.013

J Struct Biol 183:1 (2013)

PubMed id: 23726983

Crystal structure of the periplasmic disulfide-bond isomerase DsbC from Salmonella enterica serovar Typhimurium and the mechanistic implications.

L.Jiao, J.S.Kim, W.S.Song, B.Y.Yoon, K.Lee, N.C.Ha.

ABSTRACT

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.