View source for 5dqr


==The crystal structure of Arabidopsis 7-hydroxymethyl chlorophyll a reductase (HCAR)==
<StructureSection load='5dqr' size='340' side='right'caption='[[5dqr]], [[Resolution|resolution]] 2.70&Aring;' scene=''>
== Structural highlights ==
<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='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.7&#8491;</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></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>
== Function ==
[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;">
== 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<ref>PMID:27072131</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5dqr" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Arabidopsis thaliana]]
[[Category: Large Structures]]
[[Category: Liu L]]
[[Category: Wang X]]