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==Post-translational S-nitrosylation is an endogenous factor fine-tuning human S100A1 protein properties==
<StructureSection load='2llu' size='340' side='right'caption='[[2llu]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2llu]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2LLU OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2LLU FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</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=2llu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2llu OCA], [https://pdbe.org/2llu PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2llu RCSB], [https://www.ebi.ac.uk/pdbsum/2llu PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2llu ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/S10A1_HUMAN S10A1_HUMAN] Weakly binds calcium but binds zinc very tightly-distinct binding sites with different affinities exist for both ions on each monomer. Physiological concentrations of potassium ion antagonize the binding of both divalent cations, especially affecting high-affinity calcium-binding sites.
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== Publication Abstract from PubMed ==
S100A1 is a member of the Ca(2+)-binding S100 protein family. It is expressed in brain and heart tissue, where it plays a crucial role as a modulator of Ca(2+) homeostasis, energy metabolism, neurotransmitter release, and contractile performance. Biological effects of S100A1 have been attributed to its direct interaction with a variety of target proteins. The (patho)physiological relevance of S100A1 makes it an important molecular target for future therapeutic intervention. S-Nitrosylation is a post-translational modification of proteins, which plays a role in cellular signal transduction under physiological and pathological conditions. In this study, we confirmed that S100A1 protein is endogenously modified by Cys(85) S-nitrosylation in PC12 cells, which are a well established model system for studying S100A1 function. We used isothermal calorimetry to show that S-nitrosylation facilitates the formation of Ca(2+)-loaded S100A1 at physiological ionic strength conditions. To establish the unique influence of the S-nitroso group, our study describes high resolution three-dimensional structures of human apo-S100A1 protein with the Cys(85) thiol group in reduced and S-nitrosylated states. Solution structures of the proteins are based on NMR data obtained at physiological ionic strength. Comparative analysis shows that S-nitrosylation fine tunes the overall architecture of S100A1 protein. Although the typical S100 protein intersubunit four-helix bundle is conserved upon S-nitrosylation, the conformation of S100A1 protein is reorganized at the sites most important for target recognition (i.e. the C-terminal helix and the linker connecting two EF-hand domains). In summary, this study discloses cysteine S-nitrosylation as a new factor responsible for increasing functional diversity of S100A1 and helps explain the role of S100A1 as a Ca(2+) signal transmitter sensitive to NO/redox equilibrium within cells.

Post-translational S-Nitrosylation Is an Endogenous Factor Fine Tuning the Properties of Human S100A1 Protein.,Lenarcic Zivkovic M, Zareba-Koziol M, Zhukova L, Poznanski J, Zhukov I, Wyslouch-Cieszynska A J Biol Chem. 2012 Nov 23;287(48):40457-70. doi: 10.1074/jbc.M112.418392. Epub, 2012 Sep 18. PMID:22989881<ref>PMID:22989881</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[S100 proteins 3D structures|S100 proteins 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Lenarcic Zivkovic M]]
[[Category: Poznanski J]]
[[Category: Wyslouch-Cieszynska A]]
[[Category: Zareba-Koziol M]]
[[Category: Zhukov I]]
[[Category: Zhukova L]]