1dx5: Difference between revisions
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==Overview== | ==Overview== | ||
The serine proteinase alpha-thrombin causes blood clotting through, proteolytic cleavage of fibrinogen and protease-activated receptors and, amplifies its own generation by activating the essential clotting factors, V and VIII. Thrombomodulin, a transmembrane thrombin receptor with six, contiguous epidermal growth factor-like domains (TME1-6), profoundly, alters the substrate specificity of thrombin from pro- to anticoagulant by, activating protein C. Activated protein C then deactivates the coagulation, cascade by degrading activated factors V and VIII. The, thrombin-thrombomodulin complex inhibits fibrinolysis by activating the, procarboxypeptidase thrombin-activatable fibrinolysis inhibitor. Here we, present the 2.3 A crystal structure of human alpha-thrombin bound to the, smallest thrombomodulin fragment required for full protein-C co-factor, activity, TME456. The Y-shaped thrombomodulin fragment binds to thrombin's, anion-binding exosite-I, preventing binding of procoagulant substrates., Thrombomodulin binding does not seem to induce marked allosteric, structural rearrangements at the thrombin active site. Rather, docking of, a protein C model to thrombin-TME456 indicates that TME45 may bind, substrates in such a manner that their zymogen-activation cleavage sites, are presented optimally to the unaltered thrombin active site. | The serine proteinase alpha-thrombin causes blood clotting through, proteolytic cleavage of fibrinogen and protease-activated receptors and, amplifies its own generation by activating the essential clotting factors, V and VIII. Thrombomodulin, a transmembrane thrombin receptor with six, contiguous epidermal growth factor-like domains (TME1-6), profoundly, alters the substrate specificity of thrombin from pro- to anticoagulant by, activating protein C. Activated protein C then deactivates the coagulation, cascade by degrading activated factors V and VIII. The, thrombin-thrombomodulin complex inhibits fibrinolysis by activating the, procarboxypeptidase thrombin-activatable fibrinolysis inhibitor. Here we, present the 2.3 A crystal structure of human alpha-thrombin bound to the, smallest thrombomodulin fragment required for full protein-C co-factor, activity, TME456. The Y-shaped thrombomodulin fragment binds to thrombin's, anion-binding exosite-I, preventing binding of procoagulant substrates., Thrombomodulin binding does not seem to induce marked allosteric, structural rearrangements at the thrombin active site. Rather, docking of, a protein C model to thrombin-TME456 indicates that TME45 may bind, substrates in such a manner that their zymogen-activation cleavage sites, are presented optimally to the unaltered thrombin active site. | ||
==Disease== | |||
Known diseases associated with this structure: Dysprothrombinemia OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=176930 176930]], Hyperprothrombinemia OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=176930 176930]], Hypoprothrombinemia OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=176930 176930]], Myocardial infarction, susceptibility to OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=188040 188040]], Thrombophilia due to thrombomodulin defect OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=188040 188040]] | |||
==About this Structure== | ==About this Structure== | ||
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[[Category: serine proteinase]] | [[Category: serine proteinase]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 12 16:37:08 2007'' | ||