title: Structural and functional characterization of HP0377, a thioredoxin-fold protein from Helicobacter pylori.
abstract: Maturation of cytochrome c is carried out in the bacterial periplasm, where specialized thiol-disulfide oxidoreductases provide the correct reduction of oxidized apocytochrome c before covalent haem attachment. HP0377 from Helicobacter pylori is a thioredoxin-fold protein that has been implicated as a component of system II for cytochrome c assembly and shows limited sequence similarity to Escherichia coli DsbC, a disulfide-bond isomerase. To better understand the role of HP0377, its crystal structures have been determined in both reduced and partially oxidized states, which are highly similar to each other. Sedimentation-equilibrium experiments indicate that HP0377 is monomeric in solution. HP0377 adopts a thioredoxin fold but shows distinctive variations as in other thioredoxin-like bacterial periplasmic proteins. The active site of HP0377 closely resembles that of E. coli DsbC. A reductase assay suggests that HP0377 may play a role as a reductase in the biogenesis of holocytochrome c553 (HP1227). Binding experiments indicate that it can form a covalent complex with HP0518, a putative L,D-transpeptidase with a catalytic cysteine residue, via a disulfide bond. Furthermore, physicochemical properties of HP0377 and its R86A variant have been determined. These results suggest that HP0377 may perform multiple functions as a reductase in H. pylori.
authors: Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-742, Republic of Korea.
authors: Ji Young
authors: JY
authors: Yoon
authors: Jieun
authors: J
authors: Kim
authors: Doo Ri
authors: DR
authors: An
authors: Sang Jae
authors: SJ
authors: Lee
authors: Hyoun Sook
authors: HS
authors: Kim
authors: Ha Na
authors: HN
authors: Im
authors: Hye Jin
authors: HJ
authors: Yoon
authors: Jin Young
authors: JY
authors: Kim
authors: Soon Jong
authors: SJ
authors: Kim
authors: Byung Woo
authors: BW
authors: Han
authors: Se Won
authors: SW
authors: Suh
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry; D045304:Cytochromes c / Q000378:metabolism; D016480:Helicobacter pylori / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D033903:Periplasmic Proteins / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D011490:Protein Disulfide Reductase (Glutathione) / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D033903:Periplasmic Proteins; D045304:Cytochromes c; D011490:Protein Disulfide Reductase (Glutathione); D003545:Cysteine
keywords: DsbC; HP0377; HP0518; HP1227; Helicobacter pylori; cytochrome c biogenesis