Distinct characteristics of two 2-cys peroxiredoxins of Vibrio vulnificus suggesting differential roles in detoxifying oxidative stress

Ye Ji Bang, Man Hwan Oh, Sang Ho Choi

Research output: Contribution to journalArticlepeer-review

Abstract

Peroxiredoxins (Prxs) are ubiquitous antioxidant enzymes reducing toxic peroxides. Two distinct 2-Cys Prxs, Prx1 and Prx2, were identified in Vibrio vulnificus, a facultative aerobic pathogen. Both Prxs have two conserved catalytic cysteines, CP and CR, but Prx2 is more homologous in amino acid sequences to eukaryotic Prx than to Prx1. Prx2 utilized thioredoxin A as a reductant, whereas Prx1 required AhpF. Prx2 contained GGIG and FL motifs similar to the motifs conserved in sensitive Prxs and exhibited sensitivity to overoxidation. MS analysis and CP-SO3H specific immunoblotting demonstrated overoxidation of CP to C P-SO2H (or CP-SO3H) in vitro and in vivo, respectively. In contrast, Prx1 was robust and CP was not overoxidized. Discrete expression of the Prxs implied that Prx2 is induced by trace amounts of H2O2 and thereby residential in cells grown aerobically. In contrast, Prx1 was occasionally expressed only in cells exposed to high levels of H2O2. A mutagenesis study indicated that lack of Prx2 accumulated sufficient H2O2 to induce Prx1. Kinetic properties indicated that Prx2 effectively scavenges low levels of peroxides because of its high affinity to H2O2, whereas Prx1 quickly degrades higher levels of peroxides because of its high turnover rate and more efficient reactivation. This study revealed that the two Prxs are differentially optimized for detoxifying distinct ranges of H 2O2, and proposed that Prx2 is a residential scavenger of peroxides endogenously generated, whereas Prx1 is an occasional scavenger of peroxides exogenously encountered. Furthermore, genome sequence database search predicted widespread coexistence of the two Prxs among bacteria.

Original languageEnglish (US)
Pages (from-to)42516-42524
Number of pages9
JournalJournal of Biological Chemistry
Volume287
Issue number51
DOIs
StatePublished - Dec 14 2012
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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