2axt
From Proteopedia
(New page: 200px<br /><applet load="2axt" size="450" color="white" frame="true" align="right" spinBox="true" caption="2axt, resolution 3.00Å" /> '''Crystal Structure of...) |
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| - | [[Image:2axt.gif|left|200px]]<br /><applet load="2axt" size=" | + | [[Image:2axt.gif|left|200px]]<br /><applet load="2axt" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2axt, resolution 3.00Å" /> | caption="2axt, resolution 3.00Å" /> | ||
'''Crystal Structure of Photosystem II from Thermosynechococcus elongatus'''<br /> | '''Crystal Structure of Photosystem II from Thermosynechococcus elongatus'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Oxygenic photosynthesis in plants, algae and cyanobacteria is initiated at | + | Oxygenic photosynthesis in plants, algae and cyanobacteria is initiated at photosystem II, a homodimeric multisubunit protein-cofactor complex embedded in the thylakoid membrane. Photosystem II captures sunlight and powers the unique photo-induced oxidation of water to atmospheric oxygen. Crystallographic investigations of cyanobacterial photosystem II have provided several medium-resolution structures (3.8 to 3.2 A) that explain the general arrangement of the protein matrix and cofactors, but do not give a full picture of the complex. Here we describe the most complete cyanobacterial photosystem II structure obtained so far, showing locations of and interactions between 20 protein subunits and 77 cofactors per monomer. Assignment of 11 beta-carotenes yields insights into electron and energy transfer and photo-protection mechanisms in the reaction centre and antenna subunits. The high number of 14 integrally bound lipids reflects the structural and functional importance of these molecules for flexibility within and assembly of photosystem II. A lipophilic pathway is proposed for the diffusion of secondary plastoquinone that transfers redox equivalents from photosystem II to the photosynthetic chain. The structure provides information about the Mn4Ca cluster, where oxidation of water takes place. Our study uncovers near-atomic details necessary to understand the processes that convert light to chemical energy. |
==About this Structure== | ==About this Structure== | ||
| - | 2AXT is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Thermosynechococcus_elongatus Thermosynechococcus elongatus] with CA, FE2, BCT, UNK, CLA, PHO, HEM, PQ9, OEC, BCR, MGE, DGD, LHG, SQD and LMT as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 2AXT is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Thermosynechococcus_elongatus Thermosynechococcus elongatus] with <scene name='pdbligand=CA:'>CA</scene>, <scene name='pdbligand=FE2:'>FE2</scene>, <scene name='pdbligand=BCT:'>BCT</scene>, <scene name='pdbligand=UNK:'>UNK</scene>, <scene name='pdbligand=CLA:'>CLA</scene>, <scene name='pdbligand=PHO:'>PHO</scene>, <scene name='pdbligand=HEM:'>HEM</scene>, <scene name='pdbligand=PQ9:'>PQ9</scene>, <scene name='pdbligand=OEC:'>OEC</scene>, <scene name='pdbligand=BCR:'>BCR</scene>, <scene name='pdbligand=MGE:'>MGE</scene>, <scene name='pdbligand=DGD:'>DGD</scene>, <scene name='pdbligand=LHG:'>LHG</scene>, <scene name='pdbligand=SQD:'>SQD</scene> and <scene name='pdbligand=LMT:'>LMT</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2AXT OCA]. |
==Reference== | ==Reference== | ||
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[[Category: transmembrane alpha-helix]] | [[Category: transmembrane alpha-helix]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:32:06 2008'' |
Revision as of 14:32, 21 February 2008
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Crystal Structure of Photosystem II from Thermosynechococcus elongatus
Overview
Oxygenic photosynthesis in plants, algae and cyanobacteria is initiated at photosystem II, a homodimeric multisubunit protein-cofactor complex embedded in the thylakoid membrane. Photosystem II captures sunlight and powers the unique photo-induced oxidation of water to atmospheric oxygen. Crystallographic investigations of cyanobacterial photosystem II have provided several medium-resolution structures (3.8 to 3.2 A) that explain the general arrangement of the protein matrix and cofactors, but do not give a full picture of the complex. Here we describe the most complete cyanobacterial photosystem II structure obtained so far, showing locations of and interactions between 20 protein subunits and 77 cofactors per monomer. Assignment of 11 beta-carotenes yields insights into electron and energy transfer and photo-protection mechanisms in the reaction centre and antenna subunits. The high number of 14 integrally bound lipids reflects the structural and functional importance of these molecules for flexibility within and assembly of photosystem II. A lipophilic pathway is proposed for the diffusion of secondary plastoquinone that transfers redox equivalents from photosystem II to the photosynthetic chain. The structure provides information about the Mn4Ca cluster, where oxidation of water takes place. Our study uncovers near-atomic details necessary to understand the processes that convert light to chemical energy.
About this Structure
2AXT is a Protein complex structure of sequences from Thermosynechococcus elongatus with , , , , , , , , , , , , , and as ligands. Full crystallographic information is available from OCA.
Reference
Towards complete cofactor arrangement in the 3.0 A resolution structure of photosystem II., Loll B, Kern J, Saenger W, Zouni A, Biesiadka J, Nature. 2005 Dec 15;438(7070):1040-4. PMID:16355230
Page seeded by OCA on Thu Feb 21 16:32:06 2008
Categories: Protein complex | Thermosynechococcus elongatus | Biesiadka, J. | Kern, J. | Loll, B. | Saenger, W. | Zouni, A. | BCR | BCT | CA | CLA | DGD | FE2 | HEM | LHG | LMT | MGE | OEC | PHO | PQ9 | SQD | UNK | Membrane complex | Photosystem | Ps ii | Ps2 | Transmembrane alpha-helix
