Characterization of a signaling complex composed of sensory rhodopsin I and its cognate transducer protein from the eubacterium Salinibacter ruber

Yuki Sudo, Akiko Okada, Daisuke Suzuki, Keiichi Inoue, Hiroki Irieda, Makoto Sakai, Masaaki Fujii, Yuji Furutani, Hideki Kandori, Michio Homma

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25 Citations (Scopus)

Abstract

Sensory rhodopsin I (SRI) exists in the cell membranes of microorganisms such as the archaeon Halobacterium salinarum and is a photosensor responsible for positive and negative phototaxis. SRI forms a signaling complex with its cognate transducer protein, HtrI, in the membrane. That complex transmits light signals to the flagellar motor through changes in protein-protein interactions with the kinase CheA and the adaptor protein CheW, which controls the direction of the rotation of the flagellar motor. Recently, we cloned and characterized Salinibacter sensory rhodopsin I (SrSRI), which is the first SRI-like protein identified in eubacteria [Kitajima-Ihara, T., et al. (2008) J. Biol. Chem. 283, 23533-23541]. Here we cloned and expressed SrSRI with its full-length transducer protein, SrHtrI, as a fusion construct. We succeeded in producing the complex in Escherichia coli as a recombinant protein with high quality having all-trans-retinal as a chromophore for SRI, although the expression level was low (0.10 mg/L of culture). In addition, we report here the photochemical properties of the SrSRI-SrHtrI complex using time-resolved laser flash spectroscopy and other spectroscopic techniques and compare them to SrSRI without SrHtrI.

Original languageEnglish
Pages (from-to)10136-10145
Number of pages10
JournalBiochemistry
Volume48
Issue number42
DOIs
Publication statusPublished - Oct 27 2009
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry

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  • Cite this

    Sudo, Y., Okada, A., Suzuki, D., Inoue, K., Irieda, H., Sakai, M., Fujii, M., Furutani, Y., Kandori, H., & Homma, M. (2009). Characterization of a signaling complex composed of sensory rhodopsin I and its cognate transducer protein from the eubacterium Salinibacter ruber. Biochemistry, 48(42), 10136-10145. https://doi.org/10.1021/bi901338d