3BZ1: Crystal Structure of Cyanobacterial Photosystem II

Citation:
Abstract
Photosystem II (PSII) is a large homodimeric protein-cofactor complex located in the photosynthetic thylakoid membrane that acts as light-driven water:plastoquinone oxidoreductase. The crystal structure of PSII from Thermosynechococcus elongatus at 2.9-A resolution allowed the unambiguous assignment of all 20 protein subunits and complete modeling of all 35 chlorophyll a molecules and 12 carotenoid molecules, 25 integral lipids and 1 chloride ion per monomer. The presence of a third plastoquinone Q(C) and a second plastoquinone-transfer channel, which were not observed before, suggests mechanisms for plastoquinol-plastoquinone exchange, and we calculated other possible water or dioxygen and proton channels. Putative oxygen positions obtained from a Xenon derivative indicate a role for lipids in oxygen diffusion to the cytoplasmic side of PSII. The chloride position suggests a role in proton-transfer reactions because it is bound through a putative water molecule to the Mn(4)Ca cluster at a distance of 6.5 A and is close to two possible proton channels.
MMDB ID: 99467
PDB Deposition Date: 2008/1/17
Updated in MMDB: 2012/08 
Experimental Method:
x-ray diffraction
Resolution: 2.9  Å
Source Organism:
Similar Structures:
Merged PDB IDs:3BZ1 3BZ2
Asymmetric Unit: 40-meric
Molecular Components
Label Count Molecule
Proteins (40 molecules)
2
Photosystem Q(b) Protein
Molecule annotation
2
Photosystem II Core Light Harvesting Protein
Molecule annotation
2
Photosystem II Cp43 Protein
Molecule annotation
2
Photosystem II Reaction Center D2 Protein
Molecule annotation
2
Cytochrome B559 Subunit Alpha
Molecule annotation
2
Cytochrome B559 Subunit Beta
Molecule annotation
2
Photosystem II Reaction Center Protein H
Molecule annotation
2
Photosystem II Reaction Center Protein I
Molecule annotation
2
Photosystem II Reaction Center Protein J
Molecule annotation
2
Photosystem II Reaction Center Protein K
Molecule annotation
2
Photosystem II Reaction Center Protein L
Molecule annotation
2
Photosystem II Reaction Center Protein M
Molecule annotation
2
Photosystem II Manganese-stabilizing Polypeptide
Molecule annotation
2
Photosystem II Reaction Center Protein T
Molecule annotation
2
Photosystem II 12 KDA Extrinsic Protein
Molecule annotation
2
Cytochrome C-550
Molecule annotation
2
Protein Ycf12
Molecule annotation
2
Photosystem II Psbx Protein
Molecule annotation
2
Photosystem II Protein Y
Molecule annotation
2
Photosystem II Reaction Center Protein Z
Molecule annotation
Chemicals (184 molecules)
1
4
2
2
3
2
4
70
5
4
6
4
7
6
8
2
9
24
10
14
11
4
12
10
13
22
14
14
15
2
* Click molecule labels to explore molecular sequence information.

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