title: Functional similarities of a thermostable protein-disulfide oxidoreductase identified in the archaeon Pyrococcus horikoshii to bacterial DsbA enzymes.
abstract: We have isolated and characterized a gene for a putative protein-disulfide oxidoreductase (phdsb) in the archaeon Pyrococcus horikoshii. The open reading frame of phdsb encodes a protein of 170 amino acids with an NH(2)-terminal extension similar to the bacterial signal peptides. The putative mature region of PhDsb includes a sequence motif, Cys-Pro-His-Cys (CPHC), that is conserved in members of the bacterial DsbA family, but otherwise the archaeal and bacterial sequences do not show substantial similarity. A recombinant protein corresponding to the predicted mature form of PhDsb behaved as a monomer and manifested oxidoreductase activities in vitro similar to those of DsbA of Escherichia coli. The catalytic activity of PhDsb was thermostable and was shown by mutation analysis to depend on the NH(2)-terminal cysteine residue of the CPHC motif. Thus, in spite of their low overall sequence similarities, DsbA-like proteins of archaea and bacteria appear to be highly similar in terms of function.
authors.affiliation: Graduate School of Science and Engineering, Ehime University, Bunkyo-cho, Matsuyama, Ehime, 790-8577, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Kuroita
authors.forename: Takuya
authors.initials: T
authors.lastname: Kanno
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kawai
authors.forename: Bunsei
authors.initials: B
authors.lastname: Kawakami
authors.forename: Masanori
authors.initials: M
authors.lastname: Oka
authors.forename: Yaeta
authors.initials: Y
authors.lastname: Endo
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Tozawa
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D030562:Databases, Protein; D004795:Enzyme Stability; D008969:Molecular Sequence Data; D009154:Mutation; D011490:Protein Disulfide Reductase (Glutathione) / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019704:Protein Disulfide-Isomerases / Q000737:chemistry / Q000378:metabolism*; D021382:Protein Sorting Signals; D043902:Pyrococcus horikoshii / Q000201:enzymology* / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D013696:Temperature
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D011490:Protein Disulfide Reductase (Glutathione); D019704:Protein Disulfide-Isomerases