View source for 1hag


==THE ISOMORPHOUS STRUCTURES OF PRETHROMBIN2, HIRUGEN-AND PPACK-THROMBIN: CHANGES ACCOMPANYING ACTIVATION AND EXOSITE BINDING TO THROMBIN==
<StructureSection load='1hag' size='340' side='right'caption='[[1hag]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1hag]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Hirme Hirme] and [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HAG OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1HAG FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</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='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=1hag FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1hag OCA], [http://pdbe.org/1hag PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1hag RCSB], [http://www.ebi.ac.uk/pdbsum/1hag PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1hag ProSAT]</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/HIR2P_HIRME HIR2P_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/ha/1hag_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/main_output.php?pdb_ID=1hag ConSurf].
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== Publication Abstract from PubMed ==
The X-ray crystal structure of prethrombin2 (pre2), the immediate inactive precursor of alpha-thrombin, has been determined at 2.0 A resolution complexed with hirugen. The structure has been refined to a final R-value of 0.169 using 14,211 observed reflections in the resolution range 8.0-2.0 A. A total of 202 water molecules have also been located in the structure. Comparison with the hirugen-thrombin complex showed that, apart from the flexible beginning and terminal regions of the molecule, there are 4 polypeptide segments in pre2 differing in conformation from the active enzyme (Pro 186-Asp 194, Gly 216-Gly 223, Gly 142-Pro 152, and the Arg 15-Ile 16 cleavage region). The formation of the Ile 16-Asp 194 ion pair and the specificity pocket are characteristic of serine protease activation with the conformation of the catalytic triad being conserved. With the determination of isomorphous structures of hirugen-thrombin and D-Phe-Pro-Arg chloromethyl ketone (PPACK)-thrombin, the changes that occur in the active site that affect the kinetics of chromogenic substrate hydrolysis on binding to the fibrinogen recognition exosite have been determined. The backbone of the Ala 190-Gly 197 segment in the active site has an average RMS difference of 0.55 A between the 2 structures (about 3.7 sigma compared to the bulk structure). This segment has 2 type II beta-bends, the first bend showing the largest shift due to hirugen binding. Another important feature was the 2 different conformations of the side chain of Glu 192. The side chain extends to solvent in hirugen-thrombin, which is compatible with the binding of substrates having an acidic residue in the P3 position (protein-C, thrombin platelet receptor). In PPACK-thrombin, the side chain of Asp 189 and the segment Arg 221A-Gly 223 move to provide space for the inhibitor, whereas in hirugen-thrombin, the Ala 190-Gly 197 movement expands the active site region. Although 8 water molecules are expelled from the active site with PPACK binding, the inhibitor complex is resolvated with 5 other water molecules.

The isomorphous structures of prethrombin2, hirugen-, and PPACK-thrombin: changes accompanying activation and exosite binding to thrombin.,Vijayalakshmi J, Padmanabhan KP, Mann KG, Tulinsky A Protein Sci. 1994 Dec;3(12):2254-71. PMID:7756983<ref>PMID:7756983</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: Hirme]]
[[Category: Human]]
[[Category: Large Structures]]
[[Category: Thrombin]]
[[Category: Tulinsky, A]]
[[Category: Vijayalakshmi, J]]
[[Category: Hydrolase-hydrolase inhibitor complex]]