1q90: Difference between revisions

Revision as of 15:37, 21 February 2008

Structure of the cytochrome b6f (plastohydroquinone : plastocyanin oxidoreductase) from Chlamydomonas reinhardtii

OverviewOverview

Photosystems I and II (PSI and II) are reaction centres that capture light energy in order to drive oxygenic photosynthesis; however, they can only do so by interacting with the multisubunit cytochrome b(6)f complex. This complex receives electrons from PSII and passes them to PSI, pumping protons across the membrane and powering the Q-cycle. Unlike the mitochondrial and bacterial homologue cytochrome bc(1), cytochrome b(6)f can switch to a cyclic mode of electron transfer around PSI using an unknown pathway. Here we present the X-ray structure at 3.1 A of cytochrome b(6)f from the alga Chlamydomonas reinhardtii. The structure bears similarities to cytochrome bc(1) but also exhibits some unique features, such as binding chlorophyll, beta-carotene and an unexpected haem sharing a quinone site. This haem is atypical as it is covalently bound by one thioether linkage and has no axial amino acid ligand. This haem may be the missing link in oxygenic photosynthesis.

About this StructureAbout this Structure

1Q90 is a Protein complex structure of sequences from Chlamydomonas reinhardtii with , , , , , , and as ligands. Active as Plastoquinol--plastocyanin reductase, with EC number 1.10.99.1 Full crystallographic information is available from OCA.

ReferenceReference

An atypical haem in the cytochrome b(6)f complex., Stroebel D, Choquet Y, Popot JL, Picot D, Nature. 2003 Nov 27;426(6965):413-8. PMID:14647374

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-[[Image:1q90.gif|left|200px]]<br /><applet load="1q90" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1q90.gif|left|200px]]<br /><applet load="1q90" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1q90, resolution 3.10&Aring;" />
 '''Structure of the cytochrome b6f (plastohydroquinone : plastocyanin oxidoreductase) from Chlamydomonas reinhardtii'''<br />
 ==Overview==
-Photosystems I and II (PSI and II) are reaction centres that capture light, energy in order to drive oxygenic photosynthesis; however, they can only, do so by interacting with the multisubunit cytochrome b(6)f complex. This, complex receives electrons from PSII and passes them to PSI, pumping, protons across the membrane and powering the Q-cycle. Unlike the, mitochondrial and bacterial homologue cytochrome bc(1), cytochrome b(6)f, can switch to a cyclic mode of electron transfer around PSI using an, unknown pathway. Here we present the X-ray structure at 3.1 A of, cytochrome b(6)f from the alga Chlamydomonas reinhardtii. The structure, bears similarities to cytochrome bc(1) but also exhibits some unique, features, such as binding chlorophyll, beta-carotene and an unexpected, haem sharing a quinone site. This haem is atypical as it is covalently, bound by one thioether linkage and has no axial amino acid ligand. This, haem may be the missing link in oxygenic photosynthesis.
+Photosystems I and II (PSI and II) are reaction centres that capture light energy in order to drive oxygenic photosynthesis; however, they can only do so by interacting with the multisubunit cytochrome b(6)f complex. This complex receives electrons from PSII and passes them to PSI, pumping protons across the membrane and powering the Q-cycle. Unlike the mitochondrial and bacterial homologue cytochrome bc(1), cytochrome b(6)f can switch to a cyclic mode of electron transfer around PSI using an unknown pathway. Here we present the X-ray structure at 3.1 A of cytochrome b(6)f from the alga Chlamydomonas reinhardtii. The structure bears similarities to cytochrome bc(1) but also exhibits some unique features, such as binding chlorophyll, beta-carotene and an unexpected haem sharing a quinone site. This haem is atypical as it is covalently bound by one thioether linkage and has no axial amino acid ligand. This haem may be the missing link in oxygenic photosynthesis.
 ==About this Structure==
-Q90 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Chlamydomonas_reinhardtii Chlamydomonas reinhardtii] with HEM, FES, CL1, BCR, TDS, SQD, LFA and LMG as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Plastoquinol--plastocyanin_reductase Plastoquinol--plastocyanin reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.10.99.1 1.10.99.1] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1Q90 OCA].
+Q90 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Chlamydomonas_reinhardtii Chlamydomonas reinhardtii] with <scene name='pdbligand=HEM:'>HEM</scene>, <scene name='pdbligand=FES:'>FES</scene>, <scene name='pdbligand=CL1:'>CL1</scene>, <scene name='pdbligand=BCR:'>BCR</scene>, <scene name='pdbligand=TDS:'>TDS</scene>, <scene name='pdbligand=SQD:'>SQD</scene>, <scene name='pdbligand=LFA:'>LFA</scene> and <scene name='pdbligand=LMG:'>LMG</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Plastoquinol--plastocyanin_reductase Plastoquinol--plastocyanin reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.10.99.1 1.10.99.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Q90 OCA].
 ==Reference==
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 [[Category: Choquet, Y.]]
 [[Category: Picot, D.]]
-[[Category: Popot, J.L.]]
+[[Category: Popot, J L.]]
 [[Category: Stroebel, D.]]
 [[Category: BCR]]
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 [[Category: sulfoquinovosyldiacylglycerol]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 00:29:52 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:37:07 2008''