Molecular characterization of FprB (Ferredoxin-NADP+ Reductase) in Pseudomonas putida KT2440

Yunho Lee, Jinki Yeom, Yoon Suk Kang, Juhyun Kim, Jung Suk Sung, Che Ok Jeon, Woojun Park

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The fpr gene, which encodes a ferredoxin-NADP+ reductase, is known to participate in the reversible redox reactions between NADP+/NADPH and electron carriers, such as ferredoxin or flavodoxin. The role of Fpr and its regulatory protein, FinR, in Pseudomonas putida KT2440 on the oxidative and osmotic stress responses has already been characterized [Lee at al. (2006). Biochem. Biophys. Res. Commun. 339, 1246-1254]. In the genome of P. putida KT2440, another Fpr homolog (FprB) has a 35.3% amino acid identity with Fpr. The fprB gene was cloned and expressed in Escherichia coli. The diaphorase activity assay was conducted using purified FprB to identify the ftmction of FprB. In contrast to the fpr gene, the induction of fprB was not affected by oxidative stress agents, such as paraquat, menadione, H2O2, and t-butyl hydroperoxide. However, a higher level of fprB induction was observed under osmotic stress. Targeted disruption of fprB by homologous recombination resulted in a growth defect under high osmotic conditions. Recovery of oxidatively damaged aconitase activity was faster for the fprB mutant than for the fpr mutant, yet still slower than that for the wild type. Therefore, these data suggest that the catalytic function of FprB may have evolved to augment the function of Fpr in P. putida KT2440.

Original languageEnglish
Pages (from-to)1504-1512
Number of pages9
JournalJournal of Microbiology and Biotechnology
Volume17
Issue number9
Publication statusPublished - 2007 Sep 1

Keywords

  • Aconitase
  • Ferredoxin
  • Osmotic stress
  • Oxidative stress

ASJC Scopus subject areas

  • Biotechnology
  • Applied Microbiology and Biotechnology
  • Microbiology
  • Bioengineering

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