View source for 3si4

==Human Thrombin In Complex With UBTHR104==
<StructureSection load='3si4' size='340' side='right' caption='[[3si4]], [[Resolution|resolution]] 1.27&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3si4]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3SI4 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3SI4 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=B04:D-PHENYLALANYL-N-[(1-METHYLPYRIDINIUM-2-YL)METHYL]-L-PROLINAMIDE'>B04</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</scene></td></tr>
<tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=TYS:O-SULFO-L-TYROSINE'>TYS</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[3f68|3f68]], [[1k22|1k22]], [[1k1o|1k1o]], [[3eq0|3eq0]], [[2zq1|2zq1]], [[3rlw|3rlw]]</td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Thrombin Thrombin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.5 3.4.21.5] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3si4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3si4 OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3si4 RCSB], [http://www.ebi.ac.uk/pdbsum/3si4 PDBsum]</span></td></tr>
</table>
== Disease ==
[[http://www.uniprot.org/uniprot/THRB_HUMAN THRB_HUMAN]] Defects in F2 are the cause of factor II deficiency (FA2D) [MIM:[http://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:[http://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:[http://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:[http://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 ==
[[http://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>  [[http://www.uniprot.org/uniprot/HIRV2_HIRME HIRV2_HIRME]] Hirudin is a potent thrombin-specific protease inhibitor. It forms a stable non-covalent complex with alpha-thrombin, thereby abolishing its ability to cleave fibrinogen. 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
In the present study, we investigate the impact of a tightly bound water molecule on ligand binding in the S1 pocket of thrombin. The S1 pocket contains a deeply buried deprotonated aspartate residue (Asp189) that is, due to its charged state, well hydrated in the uncomplexed state. We systematically studied the importance of this water molecule by evaluating a series of ligands that contains pyridine-type P1 side chains that could potentially alter the binding properties of this water molecule. All of the pyridine derivatives retain the original hydration state albeit sometimes with a slight perturbance. In order to prevent a direct H-bond formation with Asp189, and to create a permanent positive charge on the P1 side chain that is positioned adjacent to the Asp189 carboxylate anion, we methylated the pyridine nitrogen. This methylation resulted in displacement of water but was accompanied by a loss in binding affinity. Quantum chemical calculations of the ligand solvation free energy showed that the positively charged methylpyridinium derivatives suffer a large penalty of desolvation upon binding. Consequently, they have a substantially less favorable enthalpy of binding. In addition to the ligand desolvation penalty, the hydration shell around Asp189 has to be overcome, which is achieved in nearly all pyridinium derivatives. Only for the ortho derivative is a partial population of a water next to Asp189 found. Possibly, the gain of electrostatic interactions between the charged P1 side chain and Asp189 helps to compensate for the desolvation penalty. In all uncharged pyridine derivatives, the solvation shell remains next to Asp189, partly mediating interactions between ligand and protein. In the case of the para-pyridine derivative, a strongly disordered cluster of water sites is observed between ligand and Asp189.

Impact of ligand and protein desolvation on ligand binding to the S1 pocket of thrombin.,Biela A, Khayat M, Tan H, Kong J, Heine A, Hangauer D, Klebe G J Mol Biol. 2012 May 18;418(5):350-66. Epub 2012 Feb 21. PMID:22366545<ref>PMID:22366545</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>

==See Also==
*[[Thrombin|Thrombin]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Thrombin]]
[[Category: Biela, A]]
[[Category: Heine, A]]
[[Category: Klebe, G]]
[[Category: Blood]]
[[Category: Blood clotting]]
[[Category: Blood clotting inhibitor]]
[[Category: Blood coagulation]]
[[Category: Cleavage on pairs of basic residue]]
[[Category: Convertion of fibrinogen to fibrin]]
[[Category: Glycosylation]]
[[Category: Hydrolase]]
[[Category: Hydrolase-hydrolase inhibitor complex]]
[[Category: Kringle]]
[[Category: Serine protease]]
[[Category: Thrombin inhibitor]]