View source for 6ds2


==Crystal structure of Ni(II)-bound human calprotectin==
<StructureSection load='6ds2' size='340' side='right'caption='[[6ds2]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6ds2]] is a 8 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=6DS2 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6DS2 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]] 2.1&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=NI:NICKEL+(II)+ION'>NI</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=6ds2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6ds2 OCA], [https://pdbe.org/6ds2 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6ds2 RCSB], [https://www.ebi.ac.uk/pdbsum/6ds2 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6ds2 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/S10A8_HUMAN S10A8_HUMAN] S100A8 is a calcium- and zinc-binding protein which plays a prominent role in the regulation of inflammatory processes and immune response. It can induce neutrophil chemotaxis and adhesion. Predominantly found as calprotectin (S100A8/A9) which has a wide plethora of intra- and extracellular functions. The intracellular functions include: facilitating leukocyte arachidonic acid trafficking and metabolism, modulation of the tubulin-dependent cytoskeleton during migration of phagocytes and activation of the neutrophilic NADPH-oxidase. Activates NADPH-oxidase by facilitating the enzyme complex assembly at the cell membrane, transfering arachidonic acid, an essential cofactor, to the enzyme complex and S100A8 contributes to the enzyme assembly by directly binding to NCF2/P67PHOX. The extracellular functions involve proinfammatory, antimicrobial, oxidant-scavenging and apoptosis-inducing activities. Its proinflammatory activity includes recruitment of leukocytes, promotion of cytokine and chemokine production, and regulation of leukocyte adhesion and migration. Acts as an alarmin or a danger associated molecular pattern (DAMP) molecule and stimulates innate immune cells via binding to pattern recognition receptors such as Toll-like receptor 4 (TLR4) and receptor for advanced glycation endproducts (AGER). Binding to TLR4 and AGER activates the MAP-kinase and NF-kappa-B signaling pathways resulting in the amplification of the proinflammatory cascade. Has antimicrobial activity towards bacteria and fungi and exerts its antimicrobial activity probably via chelation of Zn(2+) which is essential for microbial growth. Can induce cell death via autophagy and apoptosis and this occurs through the cross-talk of mitochondria and lysosomes via reactive oxygen species (ROS) and the process involves BNIP3. Can regulate neutrophil number and apoptosis by an anti-apoptotic effect; regulates cell survival via ITGAM/ITGB and TLR4 and a signaling mechanism involving MEK-ERK. Its role as an oxidant scavenger has a protective role in preventing exaggerated tissue damage by scavenging oxidants. Can act as a potent amplifier of inflammation in autoimmunity as well as in cancer development and tumor spread.<ref>PMID:12626582</ref> <ref>PMID:15331440</ref> <ref>PMID:15598812</ref> <ref>PMID:15642721</ref> <ref>PMID:16258195</ref> <ref>PMID:19087201</ref> <ref>PMID:19122197</ref> <ref>PMID:19935772</ref> <ref>PMID:21487906</ref> <ref>PMID:22808130</ref> <ref>PMID:22363402</ref> 
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== Publication Abstract from PubMed ==
Calprotectin (CP, S100A8/S100A9 oligomer, MRP-8/MRP-14 oligomer) is a host-defense protein that sequesters nutrient transition metals from microbes. Each S100A8/S100A9 heterodimer contains four EF-hand domains and two transition-metal-binding sites. We investigate the effect of Ca(II) ions on the structure and Ni(II)-binding properties of human CP. By employing energy dispersive X-ray (EDX) spectroscopy, we evaluate the metal content of Ni(II)-bound CP-Ser [oligomer of S100A8(C42S) and S100A9(C3S)] crystals obtained in the absence and presence of Ca(II). We present a 2.1 A resolution crystal structure of Ni(II)-bound CP-Ser and compare this structure to a reported Ni(II)- and Ca(II)-bound CP-Ser structure [Nakashige, T. G., et al. (2017) J. Am. Chem. Soc. 139, 8828-8836]. This analysis reveals conformational changes associated with coordination of Ca(II) to the EF-hands of S100A9 and that Ca(II) binding affects the coordination number and geometry of the Ni(II) ion bound to the His3Asp site. In contrast, negligible differences are observed for the Ni(II)-His6 site in the absence and presence of Ca(II). Biochemical studies show that, whereas the His6 site has a thermodynamic preference for Ni(II) over Zn(II), the His3Asp site selects for Zn(II) over Ni(II), and relatively rapid metal exchange occurs at this site. These observations inform the working model for how CP withholds nutrient metals in the extracellular space.

Biophysical Examination of the Calcium-Modulated Nickel-Binding Properties of Human Calprotectin Reveals Conformational Change in the EF-Hand Domains and His3Asp Site.,Nakashige TG, Bowman SEJ, Zygiel EM, Drennan CL, Nolan EM Biochemistry. 2018 Jun 26. doi: 10.1021/acs.biochem.8b00415. PMID:29890074<ref>PMID:29890074</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 6ds2" style="background-color:#fffaf0;"></div>

==See Also==
*[[S100 proteins 3D structures|S100 proteins 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Drennan CL]]
[[Category: Nakashige TG]]
[[Category: Nolan EM]]