Simple method for isolation of oxygen evolving photosystem 2 core complex free of cytochrome f contamination

Abstract

This communication presents a simple method for isolation of oxygen evolving photosystem 2 (PS 2) core complex by solubilisation of PS 2 membranes with the nonionic detergent octyl-β-D-thioglucopyranoside (OTG). This complex was free of cytochrome (Cyt) f contamination and also lacked the 22 and 10 kDa proteins that may not be directly required for primary photochemistry of the PS 2 complex and water oxidation. OTG could also remove the Cyt f contamination from the PS 2-core complex isolated using octyl-β-D-glucopyranoside (OGP). The Cyt f contamination in the PS 2 complexes could potentially interfere with spectrophotometric determinations of redox states of Cytb 559 and its stoichiometry in the PS 2 complex.Additional key words: octyl-β-D-thioglucopyranoside, oxygen evolution, spinach.