Energy-transfer process in photosystem II monomer and dimer core complex of Thermosynechococcus vulucanus and Cyanidioschyzon merolae.

Abstract

Although the crystal structure of Phtosystem II(PS II) showed dimer, whether PS II functions in the monomeric or dimeric form in vivo is still under debate. PS II contains D1/D2/cytb559 complex, the core antenna proteins CP43 and CP47 and is surrounded by the peripheral light-harvesting complexes such as LHCII or phycobilisomes. In order to clarify the excitation-energy transfer (EET) dynamics between monomers in the PS II dimer oomplex, we studied the picosecond time-resolved fluorescence of PS II in its monomer and dimer preparations purified from a cyanobacterium Thermosynechococcus vulcanus and a red algae Cyanidioschyzon merolae.We found a difference between the energy transfer processes between the monomer and dimer preparations at 77K and assumed an energy transfer model that explains the mechanism of energy transfer between tfhe monomers.