Open AccessThe Bacteroides fragilis P20 scavengase homolog is important in the oxidative stress response but is not controlled by OxyR
Author(s) -
Sund Christian J.,
Greg Wells William,
Jeffrey Smith C.
Publication year - 2006
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2006.00353.x
Subject(s) - mutant , oxidative stress , peroxidase , biochemistry , chemistry , microbiology and biotechnology , wild type , inducer , reactive oxygen species , bacteroides fragilis , oxidative phosphorylation , bacteroides , biology , gene , enzyme , bacteria , genetics , antibiotics
The oxidative stress response of obligate anaerobe, Bacteroides fragilis , is partially controlled by the redox regulator OxyR but an oxyR null mutant maintains a high level of aerotolerance. Studies using two‐dimensional polyacrylamide gel electrophoresis showed that a thiol peroxidase‐scavengase, Tps, was induced during oxygen exposure of an oxyR mutant. Tps is similar to ‘atypical 2‐cysteine peroxidases’ such as scavengase p20 and it demonstrated catalytic activity against t ‐butyl hydroperoxide and H 2 O 2 . A second gene, oim , encoding a putative membrane protein, was divergently transcribed from tps . Transcriptional analysis indicated that tps and oim were coordinately regulated by oxygen induction via an OxyR‐independent mechanism. H 2 O 2 was a less potent inducer than oxygen exposure and in an oxyR mutant the mRNA levels were slightly reduced compared with the wild type. A null mutant of tps had increased sensitivity to killing by t ‐butyl hydroperoxide and oxygen but an oim mutant was similar to wild type. These data indicate that Tps is important for protection against some forms of oxidative stress.