4o6y: Difference between revisions
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==Crystal Structure of Cytochrome b561== | |||
=== | <StructureSection load='4o6y' size='340' side='right' caption='[[4o6y]], [[Resolution|resolution]] 1.70Å' scene=''> | ||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[4o6y]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Arath Arath]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4O6Y OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4O6Y FirstGlance]. <br> | |||
==Function== | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> | ||
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4o79|4o79]], [[4o7g|4o7g]]</td></tr> | |||
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">CYB561B ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=3702 ARATH])</td></tr> | |||
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Ascorbate_ferrireductase_(transmembrane) Ascorbate ferrireductase (transmembrane)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.16.5.1 1.16.5.1] </span></td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4o6y FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4o6y OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4o6y RCSB], [http://www.ebi.ac.uk/pdbsum/4o6y PDBsum]</span></td></tr> | |||
</table> | |||
== Function == | |||
[[http://www.uniprot.org/uniprot/ACFR2_ARATH ACFR2_ARATH]] Two-heme-containing cytochrome. Catalyzes ascorbate-dependent trans-membrane ferric-chelate reduction (By similarity). | [[http://www.uniprot.org/uniprot/ACFR2_ARATH ACFR2_ARATH]] Two-heme-containing cytochrome. Catalyzes ascorbate-dependent trans-membrane ferric-chelate reduction (By similarity). | ||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Vitamin C, also known as ascorbate, is required in numerous essential metabolic reactions in eukaryotes. The eukaryotic ascorbate-dependent oxidoreductase cytochrome b561 (Cyt b561), a family of highly conserved transmembrane enzymes, plays an important role in ascorbate recycling and iron absorption. Although Cyt b561 was identified four decades ago, its atomic structure and functional mechanism remain largely unknown. Here, we report the high-resolution crystal structures of cytochrome b561 from Arabidopsis thaliana in both substrate-free and substrate-bound states. Cyt b561 forms a homodimer, with each protomer consisting of six transmembrane helices and two heme groups. The negatively charged substrate ascorbate, or monodehydroascorbate, is enclosed in a positively charged pocket on either side of the membrane. Two highly conserved amino acids, Lys81 and His106, play an essential role in substrate recognition and catalysis. Our structural and biochemical analyses allow the proposition of a general electron transfer mechanism for members of the Cyt b561 family. | |||
Structure and mechanism of a eukaryotic transmembrane ascorbate-dependent oxidoreductase.,Lu P, Ma D, Yan C, Gong X, Du M, Shi Y Proc Natl Acad Sci U S A. 2014 Jan 21. PMID:24449903<ref>PMID:24449903</ref> | |||
== | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | ||
</div> | |||
[[Category: Du, M | == References == | ||
[[Category: Gong, X | <references/> | ||
[[Category: Lu, P | __TOC__ | ||
[[Category: Ma, D | </StructureSection> | ||
[[Category: Shi, Y | [[Category: Arath]] | ||
[[Category: Yan, C | [[Category: Du, M]] | ||
[[Category: Gong, X]] | |||
[[Category: Lu, P]] | |||
[[Category: Ma, D]] | |||
[[Category: Shi, Y]] | |||
[[Category: Yan, C]] | |||
[[Category: Alpha helical membrane protein]] | [[Category: Alpha helical membrane protein]] | ||
[[Category: Ascorbate-dependent oxidoreductase]] | [[Category: Ascorbate-dependent oxidoreductase]] | ||
[[Category: Oxidoreductase]] | [[Category: Oxidoreductase]] | ||
Revision as of 15:37, 25 December 2014
Crystal Structure of Cytochrome b561Crystal Structure of Cytochrome b561
Structural highlights
Function[ACFR2_ARATH] Two-heme-containing cytochrome. Catalyzes ascorbate-dependent trans-membrane ferric-chelate reduction (By similarity). Publication Abstract from PubMedVitamin C, also known as ascorbate, is required in numerous essential metabolic reactions in eukaryotes. The eukaryotic ascorbate-dependent oxidoreductase cytochrome b561 (Cyt b561), a family of highly conserved transmembrane enzymes, plays an important role in ascorbate recycling and iron absorption. Although Cyt b561 was identified four decades ago, its atomic structure and functional mechanism remain largely unknown. Here, we report the high-resolution crystal structures of cytochrome b561 from Arabidopsis thaliana in both substrate-free and substrate-bound states. Cyt b561 forms a homodimer, with each protomer consisting of six transmembrane helices and two heme groups. The negatively charged substrate ascorbate, or monodehydroascorbate, is enclosed in a positively charged pocket on either side of the membrane. Two highly conserved amino acids, Lys81 and His106, play an essential role in substrate recognition and catalysis. Our structural and biochemical analyses allow the proposition of a general electron transfer mechanism for members of the Cyt b561 family. Structure and mechanism of a eukaryotic transmembrane ascorbate-dependent oxidoreductase.,Lu P, Ma D, Yan C, Gong X, Du M, Shi Y Proc Natl Acad Sci U S A. 2014 Jan 21. PMID:24449903[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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