title: The twin-arginine leader-binding protein, DmsD, interacts with the TatB and TatC subunits of the Escherichia coli twin-arginine translocase.
abstract: The twin-arginine translocase (Tat) pathway is involved in the targeting and translocation of fully folded proteins to the inner membrane and periplasm of bacteria. Proteins that use this pathway contain a characteristic twin-arginine signal sequence, which interacts with the receptor complex formed by the TatBC subunits. Recently, the DmsD protein was discovered, which binds to the twin-arginine signal sequences of the anaerobic respiratory enzymes dimethylsulfoxide reductase (DmsABC) and trimethylamine N-oxide (TMAO) reductase. In this work, the targeting of DmsD within Escherichia coli was investigated. Using cell fractionation and Western blot analysis, DmsD is found to be associated with the inner membrane of wild-type E. coli and a dmsABC mutant E. coli under anaerobic conditions. In contrast, DmsD is predominantly found in the cytoplasmic fraction of a Delta tatABCDE strain, which suggests that DmsD interacts with the membrane-associated Tat complex. Under aerobic conditions DmsD was also found primarily in the cytoplasmic fraction of wild-type E. coli, suggesting that physiological conditions have a significant effect upon the targeting of DmsD to the inner membrane. Size exclusion chromatography data and membrane washing studies indicate that DmsD is interacting tightly with an integral membrane protein and not with the lipid component of the E. coli inner membrane. Additional investigation into the nature of this interaction revealed that the TatB and TatC subunits of the translocase are important for the interaction of DmsD with the E. coli inner membrane.
authors.affiliation: Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
authors.forename: Andriyka L
authors.initials: AL
authors.lastname: Papish
authors.forename: Carol L
authors.initials: CL
authors.lastname: Ladner
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Turner
mesh_terms: D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism* / Q000502:physiology*; D002455:Cell Division; D002462:Cell Membrane / Q000378:metabolism; D002845:Chromatography; D003593:Cytoplasm / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D007506:Iron-Sulfur Proteins; D050356:Lipid Metabolism; D008081:Liposomes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism*; D010088:Oxidoreductases / Q000737:chemistry; D010089:Oxidoreductases, N-Demethylating / Q000737:chemistry; D010940:Plant Proteins / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D021381:Protein Transport; D013347:Subcellular Fractions / Q000378:metabolism; D014508:Urea / Q000494:pharmacology
chemical_list: D002352:Carrier Proteins; C434268:DmsD protein, E coli; D029968:Escherichia coli Proteins; D047908:Intracellular Signaling Peptides and Proteins; D007506:Iron-Sulfur Proteins; D008081:Liposomes; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D010940:Plant Proteins; C473116:TatB protein, E coli; C432107:TatC protein, plant; C408585:twin-arginine translocase complex, E coli; D014508:Urea; D010088:Oxidoreductases; D010089:Oxidoreductases, N-Demethylating; C023186:trimethylamine dehydrogenase; C045664:dimethyl sulfoxide reductase