View source for 3jtc


==Importance of Mg2+ in the Ca2+-Dependent Folding of the gamma-Carboxyglutamic Acid Domains of Vitamin K-Dependent clotting and anticlotting Proteins==
<StructureSection load='3jtc' size='340' side='right'caption='[[3jtc]], [[Resolution|resolution]] 1.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3jtc]] is a 4 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=3JTC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3JTC 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]] 1.6&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CGU:GAMMA-CARBOXY-GLUTAMIC+ACID'>CGU</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=PTY:PHOSPHATIDYLETHANOLAMINE'>PTY</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=3jtc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3jtc OCA], [https://pdbe.org/3jtc PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3jtc RCSB], [https://www.ebi.ac.uk/pdbsum/3jtc PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3jtc ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/EPCR_HUMAN EPCR_HUMAN] Binds activated protein C. Enhances protein C activation by the thrombin-thrombomodulin complex; plays a role in the protein C pathway controlling blood coagulation.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Crystal structures of factor (F) VIIa/soluble tissue factor (TF), obtained under high Mg2+ (50mM Mg2+/5mM Ca2+), have three of seven Ca2+ sites in the gamma-carboxyglutamic acid (Gla) domain replaced by Mg2+ at positions 1, 4, and 7. We now report structures under low Mg2+ (2.5mM Mg2+/5mM Ca2+) as well as under high Ca2+ (5mM Mg2+/45mM Ca2+). Under low Mg2+, four Ca2+ and three Mg2+ occupy the same positions as in high-Mg2+ structures. Conversely, under low Mg2+, reexamination of the structure of Gla domain of activated Protein C (APC) complexed with soluble endothelial Protein C receptor (sEPCR) has position 4 occupied by Ca2+ and positions 1 and 7 by Mg2+. Nonetheless, in direct binding experiments, Mg2+ replaced three Ca2+ sites in the unliganded Protein C or APC. Further, the high-Ca2+ condition was necessary to replace Mg4 in the FVIIa/soluble TF structure. In biological studies, Mg2+ enhanced phospholipid binding to FVIIa and APC at physiological Ca2+. Additionally, Mg2+ potentiated phospholipid-dependent activations of FIX and FX by FVIIa/TF and inactivation of activated factor V by APC. Since APC and FVIIa bind to sEPCR involving similar interactions, we conclude that under the low-Mg2+ condition, sEPCR binding to APC-Gla (or FVIIa-Gla) replaces Mg4 by Ca4 with an attendant conformational change in the Gla domain omega-loop. Moreover, since phospholipid and sEPCR bind to FVIIa or APC via the omega-loop, we predict that phospholipid binding also induces the functional Ca4 conformation in this loop. Cumulatively, the data illustrate that Mg2+ and Ca2+ act in concert to promote coagulation and anticoagulation.

Structural and Functional Studies of gamma-Carboxyglutamic Acid Domains of Factor VIIa and Activated Protein C: Role of Magnesium at Physiological Calcium.,Vadivel K, Agah S, Messer AS, Cascio D, Bajaj MS, Krishnaswamy S, Esmon CT, Padmanabhan K, Bajaj SP J Mol Biol. 2013 Feb 20. pii: S0022-2836(13)00104-6. doi:, 10.1016/j.jmb.2013.02.017. PMID:23454357<ref>PMID:23454357</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3jtc" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Agah S]]
[[Category: Bajaj SP]]
[[Category: Cascio D]]
[[Category: Esmon C]]
[[Category: Krishnaswamy S]]
[[Category: Padmanabhan K]]
[[Category: Vadivel K]]