Isolation of Highly Active Photosystem II Particles from a Mutant of Chlamydomonas reinhardtii

Abstract

Highly active photosystem-II particles were rapidly isolated using detergents and obtained in good yield from a mutant of the green alga C. reinhardtii. The particles are completely devoid of reaction centers of photosystem I, and of the secondary electron acceptor to photosystem II. They show a specific activity (.DELTA.A of C550/unit chlorophyll) 4-7 times that of the starting material and of spinach chloroplasts; an antenna size of 40-50 chlorophyll molecules containing little light-harvesting chlorophyll a/b complex (chlorophyll a/chlorophyll b = 4-6.4); a ratio of variable to dark-adapted fluorescence yield of up to 3. Further treatment of these particles by ion-exchange chromatography largely removes 5 proteins and further decreases the antenna size with little loss in primary photoactivity.