Activation of SoxR-Dependent Transcription in <i>Pseudomonas aeruginosa</i>

• Kobayashi Kazuo

  The Institute of Scientific and Industrial Research, Osaka University

• Tagawa Seiichi

  The Institute of Scientific and Industrial Research, Osaka University

Bibliographic Information

Other Title

• Activation of SoxR-Dependent Transcription in Pseudomonas aeruginosa

Abstract

The SoxR protein of Escherichia coli responds to redox signals by activating the transcription of soxS, which encodes another transcription activator that directly stimulates oxidative stress genes. In contrast, Pseudomonas aeruginosa has an open reading frame (ORF) encoding a putative protein homologous to E. coli SoxR, but not to SoxS. Instead of a soxS homolog, ORFs encoding an unknown hypothetical protein and soxR are arranged divergently with their 5' ends separated by a 78 by region containing a sequence homologous to the SoxR-binding soxS promoter. In this study, we report the overproduction and purification of SoxR from P. aeruginosa to investigate the mechanism of gene activation by SoxR. The spectroscopic properties of the purified SoxR protein indicate that it contains a redox active iron-sulfur [2 Fe-2 S] cluster. Redox titration of the SoxR protein revealed a midpoint potential of -290 mV. The SoxR protein specifically binds a fragment of the SoxS promoter-like region in a concentration-dependent fashion, as shown by both gel mobility shift and fluorescence polarization assays. The purified SoxR stimulates the in vitro transcription of the gene encoding the hypothetical protein in P. aeruginosa. This activity was lost following reduction of the SoxR [2 Fe-2 S] clusters. The levels of mRNA in the hypothetical protein increased in paraquat-treated cells. These results indicate that P. aeruginosa SoxR is a direct transcriptional activator of the hypothetical protein, and suggest that SoxR proteins may play multiple regulatory roles as a transcription factor in addition to its protective role in oxidative stress.

Journal

• The Journal of Biochemistry

  The Journal of Biochemistry 136 (5), 607-615, 2004

  The Japanese Biochemical Society

Keywords

• iron-sulfur cluster
• Pseudomonas aeruginosa
• redox signal
• SoxR
• transcription activator

Details

• CRID: 1390001204966280832
• NII Article ID: 130003534763
• NII Article ID: 10016203449
• NII Book ID: AA00694073
• DOI: 10.1093/jb/mvh168
• COI: 1:CAS:528:DC%2BD2MXislehtb0%3D
• ISSN: 17562651
• ISSN: 0021924X
• NDL BIB ID: 7242827
• PubMed: 15632300
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I7242827
• Web Site: http://academic.oup.com/jb/article-pdf/136/5/607/2671962/mvh168.pdf
• Text Lang: en
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • PubMed
  • CiNii Articles
• Abstract License Flag: Disallowed