Antithrombin: Difference between revisions

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{{STRUCTURE_1tb6|  PDB=1tb6  | SIZE=400| SCENE= |right|CAPTION=Antithrombin (beige) complex with thrombin heavy chain (pink), light chain (green) and heparin polysaccharide, [[1tb6]] }}
<StructureSection load='3evj' size='350' side='right' caption='Glycosylated human antithrombin III complex with heparin (in green) (PDB code [[3evj]])' scene='46/466527/Cv/1'>


'''Antithrombin''' (AT) inactivates several enzymes of the coagulation cycle.  α-AT contains 4 occupied glycosylation sites and is found in blood palsma. β-AT contains only 3 occupied glycosylation sites.  AT-I refers to the absorption of thrombin to fibrin; AT-II and heparin interfere with the interactin of thrombin and fibrinogen; AT-III inactivates thrombin in plasma; AT-IV becomes activated during blood coagulation.
== Function ==


{{TOC limit|limit=2}}
'''Antithrombin''' (AT) inactivates several enzymes of the coagulation cycle. AT is relatively inactive until it binds the heparan sidechains of the microvasculature.<ref>PMID:15311269</ref><br />
▪ '''α-AT''' contains 4 occupied glycosylation sites and is found in blood palsma.<br />
▪ '''β-AT''' contains only 3 occupied glycosylation sites.<br />
▪ '''AT-I''' refers to the absorption of thrombin to fibrin.<br />
▪ '''AT-II''' and heparin interfere with the interaction of thrombin and fibrinogen.<br />
▪ '''AT-III''' inactivates thrombin in plasma.  For details see [[Student Projects for UMass Chemistry 423 Spring 2012-7|Student Projects for UMass Chemistry 423 Spring 2012-7 - Antithrombin III: Devourer of Memories]].<br />
▪ '''AT-IV''' becomes activated during blood coagulation.<br />
See details for the antithrombin pentasaccharide complex in [[Molecular Playground/Antithrombin-Heparin]].


==3D structures of antithrombin==
== Disease ==


''Updated January 2013''
AT deficiency diseases are: Acquired AT deficiency and Inherited AT deficiency. AT deficiency is involved in thrombosis and pulmonary embolism.


[[1att]] – AT-III – bovine
== Relevance ==
AT activity is enhanced upon <scene name='46/466527/Cv/4'>binding to the anticoagulant drug heparin</scene>.


[[1ant]], [[2ant]] – hAT – human
==Structural highlights==


[[1e05]] - hα-AT-III
The binding of AT to the heparans or the heparin drug is to a core pentasaccharide. The binding induces conformational change of AT.


[[1e04]] – hβ-AT-III
==3D structures of antithrombin==
 
[[Antithrombin 3D structures]]
[[1ath]], [[2znh]], [[4eb1]] – hAT-III
 
[[1dzg]], [[1oyh]], [[1t1f]], [[2beh]], [[2b4x]], [[2hij]] - hAT-III (mutant)
 
===Antithrombin binary complexes===
 
[[1azx]], [[1nq9]], [[3evj]] – hAT + heparin pentasaccharide
 
[[1e03]] – hα-AT-III + heparin pentasaccharide
 
[[1dzh]] - hAT-III (mutant) + fluorescein
 
[[2gd4]] - hAT-III (mutant) + coagulation factor X
 
[[1br8]], [[1jvq]], [[1lk6]], [[1r1l]] – hAT-III + peptide
 
===Antithrombin ternary complexes===
 
[[1sr5]] - hAT-III + prothrombin + heparin heptasaccharide
 
[[1tb6]] - hAT-III (mutant) + thrombin + heparin polysaccharide
 
[[2b5t]] - AT-III (mutant) + thrombin (mutant) + heparin polysaccharide


[[3kcg]] - hAT-III (mutant) + coagulation factor IXa + heparin pentasaccharide
</StructureSection>


== References ==
<references/>
[[Category:Topic Page]]
[[Category:Topic Page]]

Latest revision as of 12:58, 25 December 2019


Function

Antithrombin (AT) inactivates several enzymes of the coagulation cycle. AT is relatively inactive until it binds the heparan sidechains of the microvasculature.[1]

▪ α-AT contains 4 occupied glycosylation sites and is found in blood palsma.
▪ β-AT contains only 3 occupied glycosylation sites.
▪ AT-I refers to the absorption of thrombin to fibrin.
▪ AT-II and heparin interfere with the interaction of thrombin and fibrinogen.
▪ AT-III inactivates thrombin in plasma. For details see Student Projects for UMass Chemistry 423 Spring 2012-7 - Antithrombin III: Devourer of Memories.
▪ AT-IV becomes activated during blood coagulation.
See details for the antithrombin pentasaccharide complex in Molecular Playground/Antithrombin-Heparin.

Disease

AT deficiency diseases are: Acquired AT deficiency and Inherited AT deficiency. AT deficiency is involved in thrombosis and pulmonary embolism.

Relevance

AT activity is enhanced upon .

Structural highlights

The binding of AT to the heparans or the heparin drug is to a core pentasaccharide. The binding induces conformational change of AT.

3D structures of antithrombin

Antithrombin 3D structures


Glycosylated human antithrombin III complex with heparin (in green) (PDB code 3evj)

Drag the structure with the mouse to rotate

ReferencesReferences

  1. ↑ Li W, Johnson DJ, Esmon CT, Huntington JA. Structure of the antithrombin-thrombin-heparin ternary complex reveals the antithrombotic mechanism of heparin. Nat Struct Mol Biol. 2004 Sep;11(9):857-62. Epub 2004 Aug 15. PMID:15311269 doi:10.1038/nsmb811

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