View source for 4o79


==Crystal Structure of Ascorbate-bound Cytochrome b561, crystal soaked in 1 M L-ascorbate for 10 minutes==
<StructureSection load='4o79' size='340' side='right'caption='[[4o79]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4o79]] is a 2 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=4O79 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4O79 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]] 2.003&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ASC:ASCORBIC+ACID'>ASC</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=4o79 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4o79 OCA], [https://pdbe.org/4o79 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4o79 RCSB], [https://www.ebi.ac.uk/pdbsum/4o79 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4o79 ProSAT]</span></td></tr>
</table>
== Function ==
[https://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&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4o79" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Arabidopsis thaliana]]
[[Category: Large Structures]]
[[Category: Du M]]
[[Category: Gong X]]
[[Category: Lu P]]
[[Category: Ma D]]
[[Category: Shi Y]]
[[Category: Yan C]]