Characterization of NADH oxidase/NADPH polysulfide oxidoreductase and its unexpected participation in oxygen sensitivity in an anaerobic hyperthermophilic archaeon.

ABSTRACT: Many genomes of anaerobic hyperthermophiles encode multiple homologs of NAD(P)H oxidase that are thought to function in response to oxidative stress. We investigated one of the seven NAD(P)H oxidase homologs (TK1481) in the sulfur-reducing hyperthermophilic archaeon Thermococcus kodakarensis, focusing on the catalytic properties and roles in oxidative-stress defense and sulfur-dependent energy conservation. The recombinant form of TK1481 exhibited both NAD(P)H oxidase and NAD(P)H:polysulfide oxidoreductase activities. The enzyme also possessed low NAD(P)H peroxidase and NAD(P)H:elemental sulfur oxidoreductase activities under anaerobic conditions. A mutant form of the enzyme, in which the putative redox-active residue Cys43 was replaced by Ala, still showed NADH-dependent flavin adenine di

SUBMITTER: Kobori H 

PROVIDER: S-EPMC2944514 | biostudies-literature | 2010 Oct

REPOSITORIES: biostudies-literature