View source for 1iht

==CRYSTAL STRUCTURE OF THE COMPLEX OF HUMAN ALPHA-THROMBIN AND NON-HYDROLYZABLE BIFUNCTIONAL INHIBITORS, HIRUTONIN-2 AND HIRUTONIN-6==
<StructureSection load='1iht' size='340' side='right' caption='[[1iht]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1iht]] 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=1IHT OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1IHT FirstGlance]. <br>
</td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=A5R:AMINO{[(4S)-4-AMINO-9-CARBOXY-5-OXONONYL]AMINO}METHANIMINIUM'>A5R</scene>, <scene name='pdbligand=ACE:ACETYL+GROUP'>ACE</scene>, <scene name='pdbligand=DPN:D-PHENYLALANINE'>DPN</scene>, <scene name='pdbligand=FBE:(3E)-5-AMINOPENT-3-ENOIC+ACID'>FBE</scene></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=1iht FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1iht OCA], [http://pdbe.org/1iht PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1iht RCSB], [http://www.ebi.ac.uk/pdbsum/1iht 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/HIR2_HIRME HIR2_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. 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/ih/1iht_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/chain_selection.php?pdb_ID=2ata ConSurf].
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== Publication Abstract from PubMed ==
The crystal structure of the complexes of hirutonin-2 and hirutonin-6 with human alpha-thrombin have been solved and refined to R-factors of 0.169 (2.0 A resolution) and 0.162 (2.1 A), respectively. Hirutonins belong to a family of bifunctional inhibitors bearing a noncleavable moiety mimicking the scissile bond. Hirutonin-2 is an analog of (D)Phe-Pro-Arg-Gly-hirudin49-65; hirutonin-6 has the same N-terminal tripeptide connected to a shortened fibrinogen exosite-binding part by a short, nonpeptidyl linker. The hirutonin-6 molecule is well defined in the electron density with the exception of the C-terminal Leu-h61. The linker follows near the bottom of the canyon connecting the active site with the exosite, forms a short antiparallel beta-sheet-like arrangement with Leu40-Leu41 and makes van der Waals contacts with Glu39-Leu40-Leu41 of thrombin. In the thrombin-hirutonin-2 complex, the N- and C-terminal parts of the inhibitor are well ordered (except the C-terminal Gln-h65) while the central portion of the linker is partially disordered. The glycine analog in the P1' position of hirutonin-2 assumes a conformation similar to that of the canonical form (Bode and Huber (1992) Eur. J. Biochem. 204:433-451) and supports the identification of the S1' site as restricted by His57, Trp60D, Lys60F, and the Cys42-Cys58 disulfide bridge. The carbonyl oxygen of the P1 arginine residue is located in the oxyanion hole formed by the NH groups of Gly193 and Ser195, while the carbonyl carbon is positioned within a short distance, 2.8 A, from the O gamma of Ser195. This resembles the conformation of the substrate-like inhibitors bound to other serine proteases. The N-terminal (D)Phe-Pro-Arg fragment common to both inhibitors binds to thrombin in a fashion very similar to that of other inhibitors having this motif. The binding of the C-terminus of hirutonins to the fibrinogen-binding exosite is similar to that observed in hirudin and hirulog complexes.

Crystal structure of the complex of human alpha-thrombin and nonhydrolyzable bifunctional inhibitors, hirutonin-2 and hirutonin-6.,Zdanov A, Wu S, DiMaio J, Konishi Y, Li Y, Wu X, Edwards BF, Martin PD, Cygler M Proteins. 1993 Nov;17(3):252-65. PMID:8272424<ref>PMID:8272424</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Hirudin|Hirudin]]
*[[Thrombin|Thrombin]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Thrombin]]
[[Category: Cygler, M]]
[[Category: Zdanov, A]]
[[Category: Hydrolase-hydrolase inhibitor complex]]
[[Category: Serine proteinase]]