@article{oai:ir.soken.ac.jp:00003911,
 author = {渡辺, 正勝 and NARIKAWA, Rei and SUZUKI, Fumiko and YOSHIHARA, Shizue and HIGASHI, Sho-ichi and WATANABE, Masakatsu and IKEUCHI, Masahiko},
 issue = {12},
 journal = {Plant and Cell Physiology, Plant and Cell Physiology},
 month = {Dec},
 note = {Two wild-type substrains of a motile cyanobacterium Synechocystis sp. PCC 6803 show positive phototaxis toward a light source (PCC-P) and negative phototaxis away from light (PCC-N). In this study, we found that a novel two-component system of photoresponse is involved in the phototactic regulation. Inactivation of slr1212 (pixA), which encodes a photoreceptor histidine kinase, reverted the positive phototaxis of PCC-P to negative phototaxis, and inactivation of the downstream slr1213 (nixB) and slr1214 (nixC), which encode AraC-like transcription factor-type and PatA-type response regulators, respectively, reverted the negative phototaxis of PCC-N to positive phototaxis. Opposite effects of pixA and nixBC disruption implies an unexpected signal transduction pathway in the switching of positive and negative phototaxis. The blue/green-type cyanobacteriochrome GAF domain of PixA was expressed in Synechocystis and phycocyanobilin-producing Escherichia coli. The holoprotein covalently bound a chromophore phycoviolobilin and showed reversible photoconversion between the violet-(Pv, λ peak = 396 nm) and green-absorbing (Pg, λ peak = 533 nm) forms, although the protein from E. coli partially bound a precursor phycocyanobilin. These results were discussed with regard to an idea that PixA serves as a violet light receptor for switching of positive and negative phototaxis by transcriptional and functional regulation.},
 pages = {2214--2224},
 title = {Novel photosensory two-component system (PixA-NixB-NixC) involved in the regulation of positive and negative phototaxis of cyanobacterium synechocystis sp. PCC 6803},
 volume = {52},
 year = {2011}
}