View source for 3nso


==Crystal Structure of S100A3 Protein Expressed in Insect Cell==
<StructureSection load='3nso' size='340' side='right'caption='[[3nso]], [[Resolution|resolution]] 1.45&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3nso]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3NSO OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3NSO 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]] 1.45&#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=3nso FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3nso OCA], [https://pdbe.org/3nso PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3nso RCSB], [https://www.ebi.ac.uk/pdbsum/3nso PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3nso ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/S10A3_HUMAN S10A3_HUMAN] Binds both calcium and zinc. May be involved in calcium-dependent cuticle cell differentiation, hair shaft and hair cuticular barrier formation.<ref>PMID:18083705</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
S100A3, a member of the EF-hand-type Ca(2+)-binding S100 protein family, is unique in its exceptionally high cysteine content and Zn(2+) affinity. We produced human S100A3 protein and its mutants in insect cells using a baculovirus expression system. The purified wild-type S100A3 and the pseudo-citrullinated form (R51A) were crystallized with ammonium sulfate in N,N-bis(2-hydroxyethyl)glycine buffer and, specifically for postrefolding treatment, with Ca(2+)/Zn(2+) supplementation. We identified two previously undocumented disulfide bridges in the crystal structure of properly folded S100A3: one disulfide bridge is between Cys30 in the N-terminal pseudo-EF-hand and Cys68 in the C-terminal EF-hand (SS1), and another disulfide bridge attaches Cys99 in the C-terminal coil structure to Cys81 in helix IV (SS2). Mutational disruption of SS1 (C30A+C68A) abolished the Ca(2+) binding property of S100A3 and retarded the citrullination of Arg51 by peptidylarginine deiminase type III (PAD3), while SS2 disruption inversely increased both Ca(2+) affinity and PAD3 reactivity in vitro. Similar backbone structures of wild type, R51A, and C30A+C68A indicated that neither Arg51 conversion by PAD3 nor SS1 alters the overall dimer conformation. Comparative inspection of atomic coordinates refined to 2.15-1.40 A resolution shows that SS1 renders the C-terminal classical Ca(2+)-binding loop flexible, which are essential for its Ca(2+) binding properties, whereas SS2 structurally shelters Arg51 in the metal-free form. We propose a model of the tetrahedral coordination of a Zn(2+) by (Cys)(3)His residues that is compatible with SS2 formation in S100A3.

Refined crystal structures of human Ca(2+)/Zn(2+)-binding S100A3 protein characterized by two disulfide bridges.,Unno M, Kawasaki T, Takahara H, Heizmann CW, Kizawa K J Mol Biol. 2011 May 6;408(3):477-90. Epub 2011 Mar 4. PMID:21377473<ref>PMID:21377473</ref>

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

==See Also==
*[[S100 proteins 3D structures|S100 proteins 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Kizawa K]]
[[Category: Takahara H]]
[[Category: Unno M]]