Introduction of the photosystem II photosynthetic reaction center complex into the silica mesoporous materials

Abstract

We used a silica mesoporous material (SMM) that has 23 nm pore diameter inner pores of honeycomb-like hexagonal cylindrical structure in its inside as a matrix for the protein function. We introduced the dimmer complex of photosystem II (PS II) reaction centers (756 kDa) that were purified from a thermophilic cyanobacterium Thermosynechococcus vulcanus into SMM that has inner pore. The adsorption to SMM decreased the oxygen evolution activity to be about a half when measured by a Clark-type oxygen electrode. Pigment assembly as well as the protein structure are almost intact inside SMM when tested by the absorption and fluorescence spectrum. The structure and function of PS II reaction center inside the nano-scale pores will be discussed.