The 1.38 A crystal structure of DmsD protein from Salmonella typhimurium, a proofreading chaperone on the Tat pathway

Proteins. 2008 May 1;71(2):525-33. doi: 10.1002/prot.21828.


The DmsD protein is necessary for the biogenesis of dimethyl sulphoxide (DMSO) reductase in many prokaryotes. It performs a critical chaperone function initiated through its binding to the twin-arginine signal peptide of DmsA, the catalytic subunit of DMSO reductase. Upon binding to DmsD, DmsA is translocated to the periplasm via the so-called twin-arginine translocation (Tat) pathway. Here we report the 1.38 A crystal structure of the protein DmsD from Salmonella typhimurium and compare it with a close functional homolog, TorD. DmsD has an all-alpha fold structure with a notable helical extension located at its N-terminus with two solvent exposed hydrophobic residues. A major difference between DmsD and TorD is that TorD structure is a domain-swapped dimer, while DmsD exists as a monomer. Nevertheless, these two proteins have a number of common features suggesting they function by using similar mechanisms. A possible signal peptide-binding site is proposed based on structural similarities. Computational analysis was used to identify a potential GTP binding pocket on similar surfaces of DmsD and TorD structures.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / chemistry*
  • Binding Sites
  • Cloning, Molecular
  • Crystallization
  • Crystallography, X-Ray
  • Guanosine Triphosphate / metabolism
  • Models, Molecular
  • Molecular Chaperones / chemistry*
  • Molecular Sequence Data
  • Protein Structure, Secondary
  • Salmonella typhimurium / chemistry*
  • Sequence Alignment


  • Bacterial Proteins
  • Molecular Chaperones
  • Guanosine Triphosphate

Associated data

  • PDB/1S9U