A Novel Photosystem I-Type Reaction Center from an Oxygenic Prokaryote Acaryochloris Marina that Contains Chlorophyll D

Chlorophyll a that absorbs red light, supports the oxygenic photosynthesis of plants and cyanobacteria by its photochemical reactions. Neither the other pigments such as chlorophylls b, c, phycobilins and carotenoids that just harvest light of different colors and transfer energy to chlorophyll a, nor bacteriochlorophylls that are used in anoxygenic bacterial photosynthesis, have thus far been shown to replace the role of chlorophyll a in the photosystems (PS) I and II reaction center complexes of oxygenic photosynthesis. Biosynthesis of chlorophyll a, therefore, has been assumed to be preceded by the establishment of oxygenic photosynthesis. We report that the role of chlorophyll a in PS I reaction center complex can be replaced by another pigment, chlorophyll d that can absorb far-red light.