COMPARISON OF THE D1/D2/CYTOCHROME-B559 REACTION CENTER COMPLEX OF PHOTOSYSTEM 2 ISOLATED BY 2 DIFFERENT METHODS

Photosystem 2 reaction centre complexes prepared either by solubilisation with Triton X-100 and subsequent exchange into dodecyl maltoside or by a procedure involving a combination of dodecyl maltoside and LiC104, were characterised in terms of chlorophyll a, pheophytin a, β-carotene and cytochrome b559 content. Time-resolved chlorophyll fluorescence decay kinetics were measured using both types of complexes. Our data show that the isolated photosystem two reaction centre complex contain, for two pheophytin a molecules, close to six chlorophyll a, two β-carotene and one cytochrome b559. No major differences were observed in the composition or the kinetic characteristics measured in the samples prepared by the different procedures. Time-resolved fluorescence measurements indicate that more than 94% of the chlorophyll a in both preparations is coupled to the reaction centre complex. © 1990.