title: The 1.38 A crystal structure of DmsD protein from Salmonella typhimurium, a proofreading chaperone on the Tat pathway.
abstract: 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.
authors.affiliation: Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Qiu
authors.forename: Rongguang
authors.initials: R
authors.lastname: Zhang
authors.forename: T Andrew
authors.initials: TA
authors.lastname: Binkowski
authors.forename: Valentina
authors.initials: V
authors.lastname: Tereshko
authors.forename: Andrzej
authors.initials: A
authors.lastname: Joachimiak
authors.forename: Anthony
authors.initials: A
authors.lastname: Kossiakoff
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D006160:Guanosine Triphosphate / Q000378:metabolism; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry*; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D012486:Salmonella typhimurium / Q000737:chemistry*; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D018832:Molecular Chaperones; D006160:Guanosine Triphosphate