Phototaxis in the Cyanobacterium Synechocystis sp. PCC 6803: Role of Different Photoreceptors

摘要: The second cyanobacterial phytochrome Cph2 from Synechocystis sp. PCC 6803 was suggested as a part of light-stimulated signal transduction chain inhibiting movement toward blue light. has the two bilin binding sites, cysteine-129 and cysteine-1022, that might be involved in sensing red/far-red light, respectively. Here, we present data on wavelength dependence phototaxis inhibition under indicating itself is photoreceptor for this light response. We found blue-light wild-type cells occurred below transition point about 470 nm. Substitution cysteine-1022 with valine led to photomovement (cph2(-) mutant phenotype). Analysis mutants lacking N-terminal chromophore domain indicated also important function or folding protein. Furthermore, putative phytochrome-like photoreceptors encoded by genome were inactivated cph2 knockout background. Our results suggest none these potential interfere function, although inactivation taxD1 well slr1694 encoding BLUF protein reversed direction illumination strains cph2.