5dqr
From Proteopedia
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== Function == | == 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> | [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> | ||
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| - | == 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. | ||
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| - | 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> | ||
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| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | ||
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| - | <div class="pdbe-citations 5dqr" style="background-color:#fffaf0;"></div> | ||
== References == | == References == | ||
<references/> | <references/> | ||
Current revision
The crystal structure of Arabidopsis 7-hydroxymethyl chlorophyll a reductase (HCAR)
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