Function of photosynthetic reaction center complex inside silica nano-pores

Abstract

The photosynthetic reaction center complex (RC) purified from a thermophilic purple photosynthetic bacterium Thermochromatium tepidum was introduced into a folded-sheet silica mesoporous material (FSM). Adsorption of RC to FSM was determined optically and by the adsorption isotherms of N2. The FSM compounds with internal pore diameters of 7.9 and 2.7 nm adsorbed RC at 0.29 and 0.02 mg/mgFSM, respectively. Photochemical activity of RC in FSM was retained, even after heating for 10 min at temperatures higher than 60 degrees C. On the other hand, RC in solution was fully inactivated after heating at 60 degrees C. Photoreduction of DCPIP was observed in FSM. The hydrophobic silica nano-pores can, thus, provide a new environment for the membrane proteins to reveal their functions. The FSM-protein conjugate will be useful for the construction of a new probe and reaction systems.