Spectral properties of bacteriophytochrome AM1_5894 in the chlorophyll d -containing cyanobacterium Acaryochloris marina

摘要: Acaryochloris marina, a unicellular oxygenic photosynthetic cyanobacterium, has uniquely adapted to far-red light-enriched environments using red-shifted chlorophyll d. To understand red-light use in Acaryochloris, the genome of this cyanobacterium was searched for red/far-red light photoreceptors from phytochrome family, resulting identification putative bacteriophytochrome AM1_5894. AM1_5894 contains three standard domains photosensory components as well C-terminal signal transduction component consisting histidine kinase and receiver domain. The autocatalytically assemble with biliverdin covalent fashion. This assembled shows typical photoreversible conversion bacterial phytochromes ground-state absorbing (Pr) form λBV max[Pr] 705 nm, inducible (Pfr) max[Pfr] 758 nm. Surprisingly, also assembles phycocyanobilin, involving λPCB 682 nm 734 nm, respectively. Our results suggest phycocyanobilin is covalently bound AM1_5894, while mutation cysteine residue (Cys11Ser) abolishes binding. physiological function cyanobacteria containing chlorophylls discussed.