Comparison of the D1/D2/cytochrome b559 reaction centre complex of photosystem two isolated by two 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 LiClO4, were characterised in terms of chlorophyll a, pheophytin a, beta-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 beta-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.
Biochemistry Department, Imperial College, London, UK.
K
K
Gounaris
D J
DJ
Chapman
P
P
Booth
B
B
Crystall
L B
LB
Giorgi
D R
DR
Klug
G
G
Porter
J
J
Barber
D002734:Chlorophyll / Q000302:isolation & purification* / Q000378:metabolism; D003573:Cytochrome b Group / Q000302:isolation & purification* / Q000378:metabolism; D007887:Fabaceae / Q000378:metabolism; D007202:Indicators and Reagents; D007700:Kinetics; D045342:Light-Harvesting Protein Complexes; D046911:Macromolecular Substances; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins / Q000302:isolation & purification* / Q000378:metabolism; D010946:Plants, Medicinal; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry
D003573:Cytochrome b Group; D007202:Indicators and Reagents; D045342:Light-Harvesting Protein Complexes; D046911:Macromolecular Substances; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D002734:Chlorophyll; C019313:cytochrome b559