View source for 3qhc


==Crystal structure of Symerythrin from Cyanophora paradoxa, reduced with dithionite==
<StructureSection load='3qhc' size='340' side='right'caption='[[3qhc]], [[Resolution|resolution]] 1.25&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3qhc]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Cyanophora_paradoxa Cyanophora paradoxa]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3QHC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3QHC 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]] 1.25&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FE:FE+(III)+ION'>FE</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=3qhc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3qhc OCA], [https://pdbe.org/3qhc PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3qhc RCSB], [https://www.ebi.ac.uk/pdbsum/3qhc PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3qhc ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/YCX8_CYAPA YCX8_CYAPA] 
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== Publication Abstract from PubMed ==
Rubrerythrins are diiron-containing peroxidases that belong to the ferritin-like superfamily (FLSF). Here, we describe the structures of symerythrin, a novel rubrerythrin variant from the oxygenic phototroph Cyanophora paradoxa, at 1.20-1.40 A resolution in three different states: diferric, azide-bound diferric and chemically reduced. The symerythrin metallocenter has a unique eighth ligating residue compared to rubrerythrin-an additional glutamate inserted into helix A of the four-helix bundle that resides on a pi-helical segment. Otherwise, the diferric metallocenter structure is highly similar to that of characterized rubrerythrins. Azide binds the diferric center in a mu-1,1 orientation similar to how peroxide binds to diferric rubrerythrin. The structure of the diferrous metallocenter shows heterogeneity that we ascribe to the acidic pH of the crystals. In what we consider the neutral pH conformation, reduction causes a 2.0-A shift in Fe1 and the toggling of a Glu to a His ligand, as seen with rubrerythrins. The function of symerythrin remains unknown, but preliminary tests showing oxidase and peroxidase activities and the similarities of its metallocenter to other rubrerythrins suggest similar functionalities between the two despite the additional ligating glutamate in symerythrin. Of particular interest is the high internal symmetry of symerythrin, which supports the notion that its core four-helix bundle was formed by the gene duplication and fusion of a two-helix peptide. Sequence comparisons with another family in the FLSF that also has notable internal symmetry provide compelling evidence that, contrary to previous assumptions, there have been multiple gene fusion events that have generated the single-chain FLSF fold.

Symerythrin structures at atomic resolution and the origins of rubrerythrins and the ferritin-like superfamily.,Cooley RB, Arp DJ, Karplus PA J Mol Biol. 2011 Oct 14;413(1):177-94. Epub 2011 Aug 19. PMID:21872605<ref>PMID:21872605</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 3qhc" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Cyanophora paradoxa]]
[[Category: Large Structures]]
[[Category: Arp DJ]]
[[Category: Cooley RB]]
[[Category: Karplus PA]]