The Interaction Of PSII Core Complexes With Its Light Harvesting Complexes In Different Membrane Environments

The light absorption and energy transfer of photosynthesis take place in thylakoid membranes, which contain the pigment-protein complexes embedded in the lipid matrix. Photosystem II (PSII) is one of the integral multi-subunit pigment-protein complexes embedded in thylakoid membranes, which uses solar energy to split water molecules into photon and molecule oxygen. Plants have developed a very complicated light harvesting system for the PSII-LHCII supercomplex, which enables efficient energy absorption and transfer to the reaction center where the primary photochemical reaction occurs. The lipid-protein interaction is a key factor mediating the structural and functional interaction among multi-subunits of PSII-LHCII supercomplex. Among the thylakoid lipids, the non-bilayer lipid monogalactosyl diacylglycerol (MGDG), which accounts for about half of the thylakoid lipids, plays an important role in the structure and function of the photosynthetic membrane proteins.The purpose of the thesis was to study the interaction between the oxygen-evolving core complexes (OECC) and its light harvesting system and the role of MGDG in the membrane made of thylakoid lipids. The studies are focused on the following points:1. MGDG and PSII can form proteoliposomes together with phosphatidylcholine (PC) or thylakoid lipids. The proteoliposomes are small and unilamellar, regularly round-shaped and have a diameter of 100-500 nm. Freeze-fractured EM has demonstrated that the LHCII complexes and OECC complexes have been integrated into the liposome membranes. The LHCII-OECC particles, with the size of about...