2GD4

Crystal Structure of the Antithrombin-S195A Factor Xa-Pentasaccharide Complex

Summary for 2GD4

• Entry DOI: 10.2210/pdb2gd4/pdb
• Related PRD ID: PRD_900028
• Descriptor: Coagulation factor X, Stuart factor, Stuart-Prower factor, Contains: Factor X light chain; Factor X heavy chain; Activated factor Xa heavy chain, Coagulation factor, Stuart factor, Stuart-Prower factor, Contains: Factor X light chain; Factor X heavy chain; Activated factor Xa heavy chain, Antithrombin-III, ... (9 entities in total)
• Functional Keywords: serpin, michaelis complex, hydrolase
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 6
• Total formula weight: 173130.35

Authors

Johnson, D.J.,Li, W.,Adams, T.E.,Huntington, J.A. (deposition date: 2006-03-15, release date: 2006-05-09, Last modification date: 2024-10-30)

Primary citation

Johnson, D.J.,Li, W.,Adams, T.E.,Huntington, J.A.
Antithrombin-S195A factor Xa-heparin structure reveals the allosteric mechanism of antithrombin activation.
Embo J., 25:2029-2037, 2006

PubMed Abstract: Regulation of blood coagulation is critical for maintaining blood flow, while preventing excessive bleeding or thrombosis. One of the principal regulatory mechanisms involves heparin activation of the serpin antithrombin (AT). Inhibition of several coagulation proteases is accelerated by up to 10,000-fold by heparin, either through bridging AT and the protease or by inducing allosteric changes in the properties of AT. The anticoagulant effect of short heparin chains, including the minimal AT-specific pentasaccharide, is mediated exclusively through the allosteric activation of AT towards efficient inhibition of coagulation factors (f) IXa and Xa. Here we present the crystallographic structure of the recognition (Michaelis) complex between heparin-activated AT and S195A fXa, revealing the extensive exosite contacts that confer specificity. The heparin-induced conformational change in AT is required to allow simultaneous contacts within the active site and two distinct exosites of fXa (36-loop and the autolysis loop). This structure explains the molecular basis of protease recognition by AT, and the mechanism of action of the important therapeutic low-molecular-weight heparins.

PubMed: 16619025
DOI: 10.1038/sj.emboj.7601089

Experimental method

X-RAY DIFFRACTION (3.3 Å)