title: The thioredoxin domain of Neisseria gonorrhoeae PilB can use electrons from DsbD to reduce downstream methionine sulfoxide reductases.
abstract: The PilB protein from Neisseria gonorrhoeae is located in the periplasm and made up of three domains. The N-terminal, thioredoxin-like domain (NT domain) is fused to tandem methionine sulfoxide reductase A and B domains (MsrA/B). We show that the alpha domain of Escherichia coli DsbD is able to reduce the oxidized NT domain, which suggests that DsbD in Neisseria can transfer electrons from the cytoplasmic thioredoxin to the periplasm for the reduction of the MsrA/B domains. An analysis of the available complete genomes provides further evidence for this proposition in other bacteria where DsbD/CcdA, Trx, MsrA, and MsrB gene homologs are all located in a gene cluster with a common transcriptional direction. An examination of wild-type PilB and a panel of Cys to Ser mutants of the full-length protein and the individually expressed domains have also shown that the NT domain more efficiently reduces the MsrA/B domains when in the polyprotein context. Within this frame-work there does not appear to be a preference for the NT domain to reduce the proximal MsrA domain over MsrB domain. Finally, we report the 1.6A crystal structure of the NT domain. This structure confirms the presence of a surface loop that makes it different from other membrane-tethered, Trx-like molecules, including TlpA, CcmG, and ResA. Subtle differences are observed in this loop when compared with the Neisseria meningitidis NT domain structure. The data taken together supports the formation of specific NT domain interactions with the MsrA/B domains and its in vivo recycling partner, DsbD.
authors.affiliation: Hospital for Special Surgery, Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10021, USA.
authors.forename: Nathan
authors.initials: N
authors.lastname: Brot
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Collet
authors.forename: Lynnette C
authors.initials: LC
authors.lastname: Johnson
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Jönsson
authors.forename: Herbert
authors.initials: H
authors.lastname: Weissbach
authors.forename: W Todd
authors.initials: WT
authors.lastname: Lowther
mesh_terms: D001665:Binding Sites; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry; D004583:Electrons; D029968:Escherichia coli Proteins / Q000737:chemistry*; D051150:Methionine Sulfoxide Reductases; D008956:Models, Chemical; D008958:Models, Molecular; D009344:Neisseria gonorrhoeae / Q000737:chemistry*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D013879:Thioredoxins / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D029968:Escherichia coli Proteins; D013879:Thioredoxins; D010088:Oxidoreductases; C094848:DsbD electron transport protein, E coli; D051150:Methionine Sulfoxide Reductases; C027219:methionine sulfoxide reductase; D003545:Cysteine