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| | <StructureSection load='5dqr' size='340' side='right'caption='[[5dqr]], [[Resolution|resolution]] 2.70Å' scene=''> | | <StructureSection load='5dqr' size='340' side='right'caption='[[5dqr]], [[Resolution|resolution]] 2.70Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[5dqr]] is a 6 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5DQR OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=5DQR FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[5dqr]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Arabidopsis_thaliana Arabidopsis thaliana]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5DQR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5DQR FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FAD:FLAVIN-ADENINE+DINUCLEOTIDE'>FAD</scene>, <scene name='pdbligand=SF4:IRON/SULFUR+CLUSTER'>SF4</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.7Å</td></tr> |
| - | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/7-hydroxymethyl_chlorophyll_a_reductase 7-hydroxymethyl chlorophyll a reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.17.7.2 1.17.7.2] </span></td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FAD:FLAVIN-ADENINE+DINUCLEOTIDE'>FAD</scene>, <scene name='pdbligand=SF4:IRON/SULFUR+CLUSTER'>SF4</scene></td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=5dqr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5dqr OCA], [http://pdbe.org/5dqr PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5dqr RCSB], [http://www.ebi.ac.uk/pdbsum/5dqr PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5dqr ProSAT]</span></td></tr> | + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=5dqr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5dqr OCA], [https://pdbe.org/5dqr PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5dqr RCSB], [https://www.ebi.ac.uk/pdbsum/5dqr PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5dqr ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/HCAR_ARATH HCAR_ARATH]] Probable iron-sulfur flavoprotein that converts 7-hydroxymethyl chlorophyll a to chlorophyll a using ferredoxin as a reducing equivalent. Catalyzes the reduction of a hydroxymethyl group to a methyl group. Belongs to the chlorophyll catabolic enzymes (CCEs).<ref>PMID:21934147</ref> | + | [https://www.uniprot.org/uniprot/HCAR_ARATH HCAR_ARATH] Probable iron-sulfur flavoprotein that converts 7-hydroxymethyl chlorophyll a to chlorophyll a using ferredoxin as a reducing equivalent. Catalyzes the reduction of a hydroxymethyl group to a methyl group. Belongs to the chlorophyll catabolic enzymes (CCEs).<ref>PMID:21934147</ref> |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: 7-hydroxymethyl chlorophyll a reductase]] | + | [[Category: Arabidopsis thaliana]] |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Liu, L]] | + | [[Category: Liu L]] |
| - | [[Category: Wang, X]] | + | [[Category: Wang X]] |
| - | [[Category: Chlorophyll cycle]]
| + | |
| - | [[Category: Hcar]]
| + | |
| - | [[Category: Iron-sulfur flavoenzyme]]
| + | |
| - | [[Category: Oxidoreductase]]
| + | |
| Structural highlights
Function
HCAR_ARATH Probable iron-sulfur flavoprotein that converts 7-hydroxymethyl chlorophyll a to chlorophyll a using ferredoxin as a reducing equivalent. Catalyzes the reduction of a hydroxymethyl group to a methyl group. Belongs to the chlorophyll catabolic enzymes (CCEs).[1]
Publication Abstract from PubMed
7-Hydroxymethyl chlorophyll a reductase (HCAR) catalyzes the second half-reaction in chlorophyll b to chlorophyll a conversion. HCAR is required for the degradation of light-harvesting complexes and is necessary for efficient photosynthesis by balancing the chlorophyll a/b ratio. Reduction of the hydroxymethyl group uses redox cofactors [4Fe-4S] cluster and FAD to transfer electrons and is difficult because of the strong carbon-oxygen bond. Here, we report the crystal structure of Arabidopsis HCAR at 2.7-A resolution and reveal that two [4Fe-4S]clusters and one FAD within a very short distance form a consecutive electron pathway to the substrate pocket. In vitro kinetic analysis confirms the ferredoxin-dependent electron transport chain, thus supporting a proton-activated electron transfer mechanism. HCAR resembles a partial reconstruction of an archaeal F420-reducing [NiFe] hydrogenase, which suggests a common mode of efficient proton-coupled electron transfer through conserved cofactor arrangements. Furthermore, the trimeric form of HCAR provides a biological clue of its interaction with light-harvesting complex II.
Crystal Structure and Catalytic Mechanism of 7-Hydroxymethyl Chlorophyll a Reductase.,Wang X, Liu L J Biol Chem. 2016 Jun 17;291(25):13349-59. doi: 10.1074/jbc.M116.720342. Epub, 2016 Apr 12. PMID:27072131[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Meguro M, Ito H, Takabayashi A, Tanaka R, Tanaka A. Identification of the 7-hydroxymethyl chlorophyll a reductase of the chlorophyll cycle in Arabidopsis. Plant Cell. 2011 Sep;23(9):3442-53. doi: 10.1105/tpc.111.089714. Epub 2011 Sep, 20. PMID:21934147 doi:http://dx.doi.org/10.1105/tpc.111.089714
- ↑ Wang X, Liu L. Crystal Structure and Catalytic Mechanism of 7-Hydroxymethyl Chlorophyll a Reductase. J Biol Chem. 2016 Jun 17;291(25):13349-59. doi: 10.1074/jbc.M116.720342. Epub, 2016 Apr 12. PMID:27072131 doi:http://dx.doi.org/10.1074/jbc.M116.720342
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