Abstract
In certain cyanobacteria, green-light irradiation induces accumulation of a green-absorbing pigment, phycoerythrin, whereas red-light irradiation induces accumulation of a red-absorbing pigment, phycocyanin, in the photosynthetic light-harvesting phycobilisome. In this study, we show that genes of a cyanobacteriochrome CcaS and cognate response regulator CcaR are essential for green light induced PE accumulation in Nostoc punctiforme ATCC 29133 that performs group II chromatic adaptation. In addition, we analyzed the chromophore-binding domain of another cyanobacteriochrome RcaE that is suggested to regulate group III chromatic adaptation in Fremyella diplosiphon. We will discuss about molecular mechanism and evolution of CcaS and RcaE with two different types of complementary chromatic adaptation.
