View source for 3guf


==Crystal Structure of the hspA from Xanthomonas axonopodis==
<StructureSection load='3guf' size='340' side='right'caption='[[3guf]], [[Resolution|resolution]] 2.28&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3guf]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Xanthomonas_citri Xanthomonas citri]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3GUF OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3GUF 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]] 2.28&#8491;</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=3guf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3guf OCA], [https://pdbe.org/3guf PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3guf RCSB], [https://www.ebi.ac.uk/pdbsum/3guf PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3guf ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q8PNC2_XANAC Q8PNC2_XANAC] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Small heat shock proteins (sHsps) are ubiquitous low-molecular-weight chaperones that prevent protein aggregation under cellular stresses. sHsps contain a structurally conserved alpha-crystallin domain (ACD) of about 100 amino acid residues flanked by varied N- and C-terminal extensions and usually exist as oligomers. Oligomerization is important for the biological functions of most sHsps. However, the active oligomeric states of sHsps are not defined yet. We present here crystal structures (up to 1.65 A resolution) of the sHspA from the plant pathogen Xanthomonas (XaHspA). XaHspA forms closed or open trimers of dimers (hexamers) in crystals but exists predominantly as 36mers in solution as estimated by size-exclusion chromatography. The XaHspA monomer structures mainly consist of alpha-crystallin domain with disordered N- and C-terminal extensions, indicating that the extensions are flexible and not essential for the formation of dimers and 36mers. Under reducing conditions where alpha-lactalbumin (LA) unfolds and aggregates, XaHspA 36mers formed complexes with one LA per XaHspA dimer. Based on XaHspA dimer-dimer interactions observed in crystals, we propose that XaHspA 36mers have four possible conformations, but only XaHspA 36merB, which is formed by open hexamers in 12mer-6mer-6mer-12mer with protruding dimers accessible for substrate (unfolding protein) binding, can bind to 18 reduced LA molecules. Together, our results unravel the structural basis of an active sHsp oligomer.

Crystal structures of Xanthomonas small heat shock protein provide a structural basis for an active molecular chaperone oligomer.,Hilario E, Martin FJ, Bertolini MC, Fan L J Mol Biol. 2011 Apr 22;408(1):74-86. Epub 2011 Feb 15. PMID:21315085<ref>PMID:21315085</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3guf" style="background-color:#fffaf0;"></div>

==See Also==
*[[Heat Shock Protein structures|Heat Shock Protein structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Xanthomonas citri]]
[[Category: Bertolini MC]]
[[Category: Hilario E]]
[[Category: Medrano FJ]]