View source for 5iix


==Crystal structure of Equine Serum Albumin in the presence of 15 mM zinc at pH 6.5==
<StructureSection load='5iix' size='340' side='right'caption='[[5iix]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5iix]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Equus_caballus Equus caballus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5IIX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5IIX 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]] 2.2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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=5iix FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5iix OCA], [https://pdbe.org/5iix PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5iix RCSB], [https://www.ebi.ac.uk/pdbsum/5iix PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5iix ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/ALBU_HORSE ALBU_HORSE] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Zinc is an essential nutrient in the body; it is required for the catalytic activity of many hundreds of human enzymes and virtually all biological processes, therefore its homeostasis and trafficking is of crucial interest. Serum albumin is the major carrier of Zn(2+) in the blood and is required for its systemic distribution. Here we present the first crystal structures of human serum albumin (HSA) and equine serum albumin (ESA) in complex with Zn(2+). The structures allow unambiguous identification of the major zinc binding site on these two albumins, as well as several further, weaker zinc binding sites. The major site in both HSA and ESA has tetrahedral geometry and comprises three protein ligands from the sidechains of His67, His247 and Asp249 and a water molecule. Isothermal titration calorimetric studies of a HSA H67A mutant confirm this to be the highest affinity Zn(2+) site. Furthermore, analysis of Zn(2+) binding to HSA and ESA proved the presence of secondary sites with 20-50-fold weaker affinities, which may become of importance under particular physiological conditions. Both calorimetry and crystallography suggest that ESA possesses an additional site compared to HSA, involving Glu153, His157 and His288. The His157 residue is replaced by Phe in HSA, incapable of metal coordination. Collectively, these findings are critical to our understanding of the role serum albumin plays in circulatory Zn(2+) handling and cellular delivery.

Circulatory zinc transport is controlled by distinct interdomain sites on mammalian albumins.,Handing KB, Shabalin IG, Kassaar O, Khazaipoul S, Blindauer CA, Stewart AJ, Chruszcz M, Minor W Chem Sci. 2016 Nov 1;7(11):6635-6648. doi: 10.1039/c6sc02267g. Epub 2016 Aug 15. PMID:28567254<ref>PMID:28567254</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5iix" style="background-color:#fffaf0;"></div>

==See Also==
*[[Albumin 3D structures|Albumin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Equus caballus]]
[[Category: Large Structures]]
[[Category: Almo SC]]
[[Category: Cooper DR]]
[[Category: Gasiorowska OA]]
[[Category: Handing KB]]
[[Category: Minor W]]
[[Category: Shabalin IG]]