Comparison of the Dl/D2/cytochrome b559 reaction centre complex of photosystem two isolated by two different methods

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Abstract
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.