title: Molecular cloning and sequence analysis of the gene encoding the H2O-forming NADH oxidase from Streptococcus mutans.
abstract: To discover the molecular properties of two distinct NADH oxidases, corresponding to H2O2-forming oxidase (NOX-1) and H2O-forming oxidase (NOX-2) induced in Streptococcus mutans, for the first step we had cloned and sequenced the nox-1 gene encoding NOX-1. In this paper, a nox-2 gene encoding NOX-2 from S. mutans was cloned, and the nucleotides sequenced. The nox-2 gene comprises 1371 base-pairs, encoding a polypeptide of 457 amino acid residues. The deduced relative molecular mass (M(r) = 49919) agreed with the previous value obtained from the purified NOX-2 protein. The nox-2 gene was expressed in Escherichia coli using its own promoter. Alignment of the NOX-2 protein sequence with that of the NOX-1 showed that the proteins do not significantly resemble each other. Comparisons with the NADH oxidase from Streptococcus faecalis 10C1 yield identities of 41%. The redox-active cysteine in the enzyme from S. faecalis was found to correspond to Cys 44 in the NOX-2.
authors.affiliation: Research Center, Nippon Paint Co., Ltd., Osaka, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Matsumoto
authors.forename: M
authors.initials: M
authors.lastname: Higuchi
authors.forename: M
authors.initials: M
authors.lastname: Shimada
authors.forename: Y
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Kamio
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D003001:Cloning, Molecular; D003545:Cysteine / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D013293:Enterococcus faecalis / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D010084:Oxidation-Reduction; D011401:Promoter Regions, Genetic / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013295:Streptococcus mutans / Q000201:enzymology* / Q000235:genetics; D014867:Water / Q000378:metabolism
chemical_list: D009097:Multienzyme Complexes; D014867:Water; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D003545:Cysteine