Photosystem I and II Reaction Centers in a New Type Oxygenic Photosynthesis of Acaryochloris marina Based on Chlorophyll d: Studies of Delayed Fluorescence and Triplet State ESR

A cyanobacteria-like organism Aaryochloris marina performs oxygenic photosynthesis with near far-red light by the use of chlorophyll d. Reaction center chlorophyll (Chl) of Photosystem (PS) II of A. marina was studied by analysis of millisecond-delayed fluorescence. Delayed fluorescence is emitted by Chi d indicating efficient energy transfer between antenna Chi d molecules and the unknown primary electron donor of PS II. P740 a reaction center Chl of PS I of A. marina is shown to give a dimer type cation, and triplet state with a D value of 245xlO$\^$-4/ cm$\^$-l/ in contrast to the 280-290 xlO$\^$-4/cm$\^$-l/ values of P700 suggesting triplet spins interacting at a 5% larger distance in P740 than in P700.