View source for 1br8


==IMPLICATIONS FOR FUNCTION AND THERAPY OF A 2.9A STRUCTURE OF BINARY-COMPLEXED ANTITHROMBIN==
<StructureSection load='1br8' size='340' side='right'caption='[[1br8]], [[Resolution|resolution]] 2.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1br8]] is a 3 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=1BR8 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1BR8 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]] 2.9&#8491;</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=1br8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1br8 OCA], [https://pdbe.org/1br8 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1br8 RCSB], [https://www.ebi.ac.uk/pdbsum/1br8 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1br8 ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/ANT3_HUMAN ANT3_HUMAN] Defects in SERPINC1 are the cause of antithrombin III deficiency (AT3D) [MIM:[https://omim.org/entry/613118 613118]. AT3D is an important risk factor for hereditary thrombophilia, a hemostatic disorder characterized by a tendency to recurrent thrombosis. AT3D is classified into 4 types. Type I: characterized by a 50% decrease in antigenic and functional levels. Type II: has defects affecting the thrombin-binding domain. Type III: alteration of the heparin-binding domain. Plasma AT-III antigen levels are normal in type II and III. Type IV: consists of miscellaneous group of unclassifiable mutations.<ref>PMID:7734359</ref> [:]<ref>PMID:3191114</ref> <ref>PMID:9031473</ref> <ref>PMID:6582486</ref> <ref>PMID:3080419</ref> <ref>PMID:3805013</ref> <ref>PMID:3179438</ref> <ref>PMID:3162733</ref> <ref>PMID:2781509</ref> <ref>PMID:2365065</ref> <ref>PMID:2229057</ref> <ref>PMID:2013320</ref> <ref>PMID:1906811</ref> <ref>PMID:1555650</ref> <ref>PMID:1547341</ref> <ref>PMID:8443391</ref> <ref>PMID:8486379</ref> <ref>PMID:7981186</ref> <ref>PMID:7959685</ref> <ref>PMID:8274732</ref> <ref>PMID:7994035</ref> <ref>PMID:7989582</ref> [:]<ref>PMID:7878627</ref> <ref>PMID:7832187</ref> <ref>PMID:9157604</ref> <ref>PMID:9845533</ref> <ref>PMID:9759613</ref> <ref>PMID:10997988</ref> <ref>PMID:11794707</ref> <ref>PMID:11713457</ref> <ref>PMID:12353073</ref> <ref>PMID:12595305</ref> <ref>PMID:12894857</ref> <ref>PMID:15164384</ref> <ref>PMID:16908819</ref> 
== Function ==
[https://www.uniprot.org/uniprot/ANT3_HUMAN ANT3_HUMAN] Most important serine protease inhibitor in plasma that regulates the blood coagulation cascade. AT-III inhibits thrombin, matriptase-3/TMPRSS7, as well as factors IXa, Xa and XIa. Its inhibitory activity is greatly enhanced in the presence of heparin.<ref>PMID:15853774</ref> 
== 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/br/1br8_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1br8 ConSurf].
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== Publication Abstract from PubMed ==
The crystal structure of a binary complex of human antithrombin with a peptide of the same sequence as its reactive loop (P14-P3) has been determined at 2.9 A. The peptide binds as the middle strand s4A in the A beta-sheet, homologously to that of the reactive loop in the latent and cleaved forms of antithrombin. Peptide binding results in the complete expulsion of the hinge region of the loop from the A beta-sheet although the conformation differs from that of heparin-activated antithrombin. The 36-fold increase in the rate of reaction of the binary complex with factor Xa indicates that full loop expulsion alone is not sufficient for complete heparin activation of antithrombin but that this is also dependent on the overall conformation of the molecule. Previous studies have demonstrated that reactive loop peptides can block or reverse the polymerisation of serpins associated with cirrhosis and thrombosis. The antithrombin binary complex structure defines the precise localisation of the blocking peptide in a serpin and provides the basis for rational drug design for mimetics that will prevent polymerisation in vivo and so ameliorate the associated disease.

Implications for function and therapy of a 2.9 A structure of binary-complexed antithrombin.,Skinner R, Chang WS, Jin L, Pei X, Huntington JA, Abrahams JP, Carrell RW, Lomas DA J Mol Biol. 1998;283(1):9-14. PMID:9761669<ref>PMID:9761669</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1br8" style="background-color:#fffaf0;"></div>

==See Also==
*[[Antithrombin 3D structures|Antithrombin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Abrahams JP]]
[[Category: Carrell RW]]
[[Category: Chang WSW]]
[[Category: Huntington JA]]
[[Category: Jin L]]
[[Category: Lomas DA]]
[[Category: Pei XY]]
[[Category: Skinner R]]