Publication: Pseudomonas aeruginosa Thiol Peroxidase Protects against Hydrogen Peroxide Toxicity and Displays Atypical Patterns of Gene Regulation
3
Issued Date
2012-08-01
Resource Type
ISSN
10985530
00219193
00219193
Other identifier(s)
2-s2.0-84866342431
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Mahidol University
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SCOPUS
Bibliographic Citation
Journal of Bacteriology. Vol.194, No.15 (2012), 3904-3912
Suggested Citation
Nawarat Somprasong, Thichakorn Jittawuttipoka, Jintana Duang-Nkern, Adisak Romsang, Pimchai Chaiyen, Herbert P. Schweizer, Paiboon Vattanaviboon, Skorn Mongkolsuk Pseudomonas aeruginosa Thiol Peroxidase Protects against Hydrogen Peroxide Toxicity and Displays Atypical Patterns of Gene Regulation. Journal of Bacteriology. Vol.194, No.15 (2012), 3904-3912. doi:10.1128/JB.00347-12 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/13652
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Title
Pseudomonas aeruginosa Thiol Peroxidase Protects against Hydrogen Peroxide Toxicity and Displays Atypical Patterns of Gene Regulation
Abstract
The Pseudomonas aeruginosa PAO1 thiol peroxidase homolog (Tpx) belongs to a family of enzymes implicated in the removal of toxic peroxides. We have shown the expression of tpx to be highly inducible with redox cycling/superoxide generators and diamide and weakly inducible with organic hydroperoxides and hydrogen peroxide (H 2 O 2 ). The PAO1 tpx pattern is unlike the patterns for other peroxide-scavenging genes in P. aeruginosa. Analysis of the tpx promoter reveals the presence of a putative IscR binding site located near the promoter. The tpx expression profiles in PAO1 and the iscR mutant, together with results from gel mobility shift assays showing that purified IscR specifically binds the tpx promoter, support the role of IscR as a transcriptional repressor of tpx that also regulates the oxidant-inducible expression of the gene. ecombinant Tpx has been purified and biochemically characterized. The enzyme catalyzes thioredoxin-dependent peroxidation and can utilize organic hydroperoxides and H 2 O 2 as substrates. The Δtpx mutant demonstrates differential sensitivity to H 2 O 2 only at moderate concentrations (0.5 mM) and not at high (20 mM) concentrations, suggesting a novel protective role of tpx against H 2 O 2 in P. aeruginosa. Altogether, P. aeruginosa tpx is a novel member of the IscR regulon and plays a primary role in protecting the bacteria from submillimolar concentrations of H 2 O 2 . © 2012, American Society for Microbiology.