Molecular Cloning and Sequence Analysis of the Gene Encoding the H2O-forming NADH Oxidase From Streptococcus Mutans

Biosci Biotechnol Biochem. 1996 Jan;60(1):39-43. doi: 10.1271/bbb.60.39.


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.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Blotting, Western
  • Cloning, Molecular
  • Cysteine / metabolism
  • Electrophoresis, Polyacrylamide Gel
  • Enterococcus faecalis / genetics
  • Enterococcus faecalis / metabolism
  • Escherichia coli / genetics
  • Gene Expression Regulation, Bacterial / genetics*
  • Molecular Sequence Data
  • Molecular Weight
  • Multienzyme Complexes / genetics*
  • Multienzyme Complexes / metabolism
  • NADH, NADPH Oxidoreductases / genetics*
  • NADH, NADPH Oxidoreductases / metabolism
  • Oxidation-Reduction
  • Promoter Regions, Genetic / genetics
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Streptococcus mutans / enzymology*
  • Streptococcus mutans / genetics
  • Water / metabolism


  • Multienzyme Complexes
  • Water
  • NADH oxidase
  • NADH, NADPH Oxidoreductases
  • Cysteine

Associated data

  • GENBANK/D49951