Three-dimensional structure of the higher-plant photosystem II reaction centre and evidence for its dimeric organization in vivo.
The three-dimensional structure of photosystem II (PSII) has been determined by conventional transmission electron microscopy and computerized three-dimensional reconstruction. Both the complete system and that lacking the oxygen-evolving complex have been analyzed. The PSII complex has a four-lobed structure with twofold symmetry. An estimate of the molecular mass and the results of Deriphat/PAGE analysis suggest that a reaction centre is present in each half of the structure resolved by electron microscopy. Stepwise removal of components of the complex showed that the removal of CP47 (a 47-kDa chlorophyll-protein complex) induces monomerization of PSII, which indicates the importance of this subunit for the dimeric structure.
Santini
C
C
Dipartimento di Biologia, Università di Padova, Italy.
Tidu
V
V
Tognon
G
G
Ghiretti Magaldi
A
A
Bassi
R
R
D002462:Cell Membrane / Q000737:chemistry; D002736:Chloroplasts / Q000737:chemistry / Q000648:ultrastructure; D003198:Computer Simulation; D004591:Electrophoresis, Polyacrylamide Gel; D007091:Image Processing, Computer-Assisted; D007425:Intracellular Membranes / Q000737:chemistry; D045342:Light-Harvesting Protein Complexes; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D008958:Models, Molecular; D008970:Molecular Weight; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000648:ultrastructure; D045332:Photosystem II Protein Complex; D003313:Zea mays / Q000737:chemistry
D045342:Light-Harvesting Protein Complexes; D046911:Macromolecular Substances; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex