Chemotaxis proteins and transducers for aerotaxis in Pseudomonas aeruginosa

Authors

  • Chang Soo Hong,

    1. Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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  • Maiko Shitashiro,

    1. Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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  • Akio Kuroda,

    1. Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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  • Tsukasa Ikeda,

    1. Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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  • Noboru Takiguchi,

    1. Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
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  • Hisao Ohtake,

    1. Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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  • Junichi Kato

    Corresponding author
    1. Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
      *Corresponding author. Tel.: +81 (824) 24 7757; Fax: +81 (824) 24 7047, E-mail address: jun@hiroshima-u.ac.jp
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*Corresponding author. Tel.: +81 (824) 24 7757; Fax: +81 (824) 24 7047, E-mail address: jun@hiroshima-u.ac.jp

Abstract

It was previously shown that the chemotaxis gene cluster 1 (cheYZABW) was required for chemotaxis. In this study, the involvement of the same cluster in aerotaxis is described and two transducer genes for aerotaxis are identified. Aerotaxis assays of a number of deletion–insertion mutants of Pseudomonas aeruginosa PAO1 revealed that the chemotaxis gene cluster 1 and cheR are required for aerotaxis. Mutant strains which contained deletions in the methyl-accepting chemotaxis protein-like genes tlpC and tlpG showed decreased aerotaxis. A double mutant deficient in tlpC and tlpG was negative for aerotaxis. TlpC has 45% amino acid identity with the Escherichia coli aerotactic transducer Aer. The TlpG protein has a predicted C-terminal segment with 89% identity to the highly conserved domain of the E. coli serine chemoreceptor Tsr. A hydropathy plot of TlpG indicated that hydrophobic membrane-spanning regions are missing in TlpG. A PAS motif was found in the N-terminal domains of TlpC and TlpG. On this basis, the tlpC and tlpG genes were renamed aer and aer-2, respectively. No significant homology other than the PAS motif was detected in the N-terminal domains between Aer and Aer-2.

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