title: Disulfide-bond formation in the H+-pyrophosphatase of Streptomyces coelicolor and its implications for redox control and enzyme structure.
abstract: Redox control of disulfide-bond formation in the H+-pyrophosphatase of Streptomyces coelicolor was investigated using cysteine mutants expressed in Escherichia coli. The wild-type enzyme, but not a cysteine-less mutant, was reversibly inactivated by oxidation. To determine the residues involved in oxidative inactivation, different cysteine residues were replaced. Analysis with a cysteine-modifying reagent revealed that the formation of a disulfide bond between cysteines 253 and 621 was responsible for enzyme inactivation. This result suggests that residues in different cytoplasmic loops are close to each other in the tertiary structure. Both cysteine residues are conserved in K+-independent (type II) H+-pyrophosphatases.
authors.affiliation: Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Hisatoshi
authors.initials: H
authors.lastname: Mimura
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Nakanishi
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Maeshima
mesh_terms: D000595:Amino Acid Sequence; D003545:Cysteine / Q000235:genetics / Q000378:metabolism*; D004220:Disulfides / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D043564:Inorganic Pyrophosphatase / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010084:Oxidation-Reduction; D048372:Streptomyces coelicolor / Q000201:enzymology* / Q000235:genetics
chemical_list: D004220:Disulfides; D043564:Inorganic Pyrophosphatase; D003545:Cysteine