View source for 6pxq


==Crystal structure of human thrombin mutant D194A==
<StructureSection load='6pxq' size='340' side='right'caption='[[6pxq]], [[Resolution|resolution]] 2.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6pxq]] 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=6PXQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6PXQ 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]] 2.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</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=6pxq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6pxq OCA], [https://pdbe.org/6pxq PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6pxq RCSB], [https://www.ebi.ac.uk/pdbsum/6pxq PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6pxq ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/THRB_HUMAN THRB_HUMAN] Defects in F2 are the cause of factor II deficiency (FA2D) [MIM:[https://omim.org/entry/613679 613679]. It is a very rare blood coagulation disorder characterized by mucocutaneous bleeding symptoms. The severity of the bleeding manifestations correlates with blood factor II levels.<ref>PMID:14962227</ref> <ref>PMID:6405779</ref> <ref>PMID:3771562</ref> <ref>PMID:3567158</ref> <ref>PMID:3801671</ref> <ref>PMID:3242619</ref> <ref>PMID:2719946</ref> <ref>PMID:1354985</ref> <ref>PMID:1421398</ref> <ref>PMID:1349838</ref> <ref>PMID:7865694</ref> <ref>PMID:7792730</ref>   Genetic variations in F2 may be a cause of susceptibility to ischemic stroke (ISCHSTR) [MIM:[https://omim.org/entry/601367 601367]; also known as cerebrovascular accident or cerebral infarction. A stroke is an acute neurologic event leading to death of neural tissue of the brain and resulting in loss of motor, sensory and/or cognitive function. Ischemic strokes, resulting from vascular occlusion, is considered to be a highly complex disease consisting of a group of heterogeneous disorders with multiple genetic and environmental risk factors.<ref>PMID:15534175</ref>   Defects in F2 are the cause of thrombophilia due to thrombin defect (THPH1) [MIM:[https://omim.org/entry/188050 188050]. It is a multifactorial disorder of hemostasis characterized by abnormal platelet aggregation in response to various agents and recurrent thrombi formation. Note=A common genetic variation in the 3-prime untranslated region of the prothrombin gene is associated with elevated plasma prothrombin levels and an increased risk of venous thrombosis.  Defects in F2 are associated with susceptibility to pregnancy loss, recurrent, type 2 (RPRGL2) [MIM:[https://omim.org/entry/614390 614390]. A common complication of pregnancy, resulting in spontaneous abortion before the fetus has reached viability. The term includes all miscarriages from the time of conception until 24 weeks of gestation. Recurrent pregnancy loss is defined as 3 or more consecutive spontaneous abortions.<ref>PMID:11506076</ref> 
== Function ==
[https://www.uniprot.org/uniprot/THRB_HUMAN THRB_HUMAN] Thrombin, which cleaves bonds after Arg and Lys, converts fibrinogen to fibrin and activates factors V, VII, VIII, XIII, and, in complex with thrombomodulin, protein C. Functions in blood homeostasis, inflammation and wound healing.<ref>PMID:2856554</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Activity in trypsin-like proteases is the result of proteolytic cleavage at R15 followed by an ionic interaction that ensues between the new N terminus of I16 and the side chain of the highly conserved D194. This mechanism of activation, first proposed by Huber and Bode, organizes the oxyanion hole and primary specificity pocket for substrate binding and catalysis. Using the clotting protease thrombin as a relevant model, we unravel contributions of the I16-D194 ionic interaction to Na(+) binding, stability of the transition state and the allosteric E*-E equilibrium of the trypsin fold. The I16T mutation abolishes the I16-D194 interaction and compromises the architecture of the oxyanion hole. The D194A mutation also abrogates the I16-D194 interaction but, surprisingly, has no effect on the architecture of the oxyanion hole that remains intact through a new H-bond established between G43 and G193. In both mutants, loss of the I16-D194 ionic interaction compromises Na(+) binding, reduces stability of the transition state, collapses the 215-217 segment into the primary specific pocket and abrogates the allosteric E*-E equilibrium in favor of a rigid conformation that binds ligand at the active site according to a simple lock-and-key mechanism. These findings refine the structural role of the I16-D194 ionic interaction in the Huber-Bode mechanism of activation and reveal a functional linkage with the allosteric properties of the trypsin fold like Na(+) binding and the E*-E equilibrium.

Role of the I16-D194 ionic interaction in the trypsin fold.,Stojanovski BM, Chen Z, Koester SK, Pelc LA, Di Cera E Sci Rep. 2019 Dec 2;9(1):18035. doi: 10.1038/s41598-019-54564-6. PMID:31792294<ref>PMID:31792294</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6pxq" style="background-color:#fffaf0;"></div>

==See Also==
*[[Thrombin 3D Structures|Thrombin 3D Structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Chen Z]]
[[Category: Di Cera E]]
[[Category: Koester SK]]
[[Category: Pelc LA]]
[[Category: Stojanovski B]]