Abstract
In all the oxygenic photosynthetic organisms,Chlorophyll (Chl) plays a key role in photosynthetic energy conversion of solar energy into chemical energy. Until recently, Chl a has been believed to be essential for the light harvesting and photochemical reactions in oxygenic photosynthesis. In 1996, a new type of oxygenic photosynthetic organism, Acaryochloris marina (A.marina), was discovered. A.marina performs the oxygenic photosynthesis with Chl d that absorbs light at wavelength above 700nm, at longer wavelength than Chl a. An enigma that how to drive oxygenic photosynthesis using the10-percent-lower-energy photons compared with Chl a arose. We here analyzed the orientation of the pigments in the isolated reaction center pigment-protein complexes to understand the mechanism of excitation transfer and photochemistry with Chl d. We studied orientation and photochemistry of pigments in purified Photosystem I complexes of A.marina by using a Linear Dichroism technique.
