Abstract
The molecular assemblies of photosynthetic reaction centers (RCs) driving the light-to-redox energy conversion have been studied by chemical analytical and various spectroscopic means. As a result, one molecule of chlorophyll (Chl) a′, the C132-epimer of the dominant pigment Chl a, was detected for the first time as an essential component of photosystem I RC of higher plants, algae, and cyanobacteria. Further, two molecules each of bacteriochlorophyll (BChl) g′ and 81–OH–Chl a in heliobacterial RCs, two molecules of BChl a′ in the RC of a green sulfur bacterium Chlorobium tepidum, and one or two molecules of Chl d′ in the RC of a cyanobacterium Acaryochloris marina were detected. In addition, the chemical structure of BChl 663, the primary acceptor in the RC of green sulfur bacteria, and that of Zn–BChl a found in Acidiphilium rubrum, were determined. Detection/identification of these novel minor but key pigments would contribute to the discussion on the molecular machinery of photosynthetic reaction centers.
