Dimeric and monomeric organization of photosystem II. Distribution of five distinct complexes in the different domains of the thylakoid membrane.
The supramolecular organization of photosystem II (PSII) was characterized in distinct domains of the thylakoid membrane, the grana core, the grana margins, the stroma lamellae, and the so-called Y100 fraction. PSII supercomplexes, PSII core dimers, PSII core monomers, PSII core monomers lacking the CP43 subunit, and PSII reaction centers were resolved and quantified by blue native PAGE, SDS-PAGE for the second dimension, and immunoanalysis of the D1 protein. Dimeric PSII (PSII supercomplexes and PSII core dimers) dominate in the core part of the thylakoid granum, whereas the monomeric PSII prevails in the stroma lamellae. Considerable amounts of PSII monomers lacking the CP43 protein and PSII reaction centers (D1-D2-cytochrome b559 complex) were found in the stroma lamellae. Our quantitative picture of the supramolecular composition of PSII, which is totally different between different domains of the thylakoid membrane, is discussed with respect to the function of PSII in each fraction. Steady state electron transfer, flash-induced fluorescence decay, and EPR analysis revealed that nearly all of the dimeric forms represent oxygen-evolving PSII centers. PSII core monomers were heterogeneous, and a large fraction did not evolve oxygen. PSII monomers without the CP43 protein and PSII reaction centers showed no oxygen-evolving activity.
Danielsson
Ravi
R
Department of Biochemistry, Center for Chemistry and Chemical Engineering, P.O. Box 124, Lund University, S-221 00 Lund, Sweden.
Suorsa
Marjaana
M
Paakkarinen
Virpi
V
Albertsson
Per-Ake
PA
Styring
Stenbjörn
S
Aro
Eva-Mari
EM
Mamedov
Fikret
F
D019281:Dimerization; D004583:Electrons; D004591:Electrophoresis, Polyacrylamide Gel; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry; D008280:Magnetics; D008954:Models, Biological; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry; D045332:Photosystem II Protein Complex / Q000737:chemistry; D017434:Protein Structure, Tertiary; D018724:Spinacia oleracea / Q000502:physiology; D020524:Thylakoids / Q000378:metabolism*
D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; C083100:photosystem II, chlorophyll binding protein, CP-43; D010100:Oxygen