| Research Abstract |
The successive reaction system in the primary processes of photosynthesis was analyzed. We used biological materials, and did not construct the artificial system. We obtained the following four major results.
(1) We analyzed the energy transfer process in a newly found cyanobacterium Acaryochloris marina that is known to contain Chl d. The energy level of antenna Chl a is lower than the energy trap, however the up-hill energy transfer process was proved to function in this organism, indicating a new concept in the antenna system. We also found a new species that contains Chl d, and this leads to the final conclusion on the presence of Chl d in red algae.
(2) We proved that the spatial orientation of the special pair in the newly found Zn-BChl a containing photosynthetic bacterium Acidiphilium rubrum was different from that in the purple bacteria. A weak interaction between Zn-BChl a's suggested the modification in the reaction kinetics.
(3) we applied the normal mode analysis to the antenna protein of cyanobacteria, that is, phycobiliproteins, and concluded that the protein structure is essential for stabilizing the electronic state of chromophores that engages in the successive reaction system.
(4) We analyzed the excitation relaxation processes of carotenoids that function as an efficient antenna in algae, and found that very fast vibrational relaxationin the S2 state is essential for the antenna function.
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