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Mechanisms of Hemostatic Protease Inhibition by Serpins

丝氨酸蛋白酶抑制剂抑制止血蛋白酶的机制

基本信息

批准号：
7754418
负责人：
INGRID M VERHAMME
金额：
$ 29.78万
依托单位：
VANDERBILT UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-01-15 至 2012-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7754418
关键词：
Acylation Address Affinity Anticoagulant therapy Anticoagulants Antithrombin III Antithrombins Arterial Fatty Streak Binding Binding Sites Blood Platelets Cell surface Chemicals Coagulation Process Competitive Binding Complex Dependence Dermatan Sulfate Development Enzymes Equilibrium Event Fibrin Fibrinogen Fluorescence Glycosaminoglycans Goals Hemostatic Agents Heparin Heparin Binding Heparin Cofactor II Injury Kinetics Label Ligands Mediating Molecular Pathway interactions Peptide Hydrolases Plasminogen Activator Inhibitor 1 Play Process Proteins Reaction Regulation Research Personnel Role Rupture Serpins Site Site-Directed Mutagenesis Surface Testing Therapeutic Embolization Thrombin Thrombosis Thrombus Time Variant arginyllysine base chemical binding chemical reaction deacylation inhibitor/antagonist insight loss of function meizothrombin mutant novel percutaneous coronary intervention programs stopped-flow fluorescence

项目摘要

The long-term goal is to define the molecular mechanisms of thrombin (T) inhibition by the serpins, heparin cofactor II (HCII) and plasminogen activator inhibitor-1 (PAI-1), implicated in arterial thrombosis. Thrombin localized on fibrin (Fbn) and the glycosaminoglycans (GAGs) dermatan sulfate (DS)and heparin, reacts with HCII and platelet PAI-1, in GAG-accelerated mechanisms different from thrombin inhibition by antithrombin (AT), accelerated by high affinity heparin, present only in trace amounts. Unlike AT, HCII is a unique inhibitor of arterial thrombosis, as only HCII in the presence of DS is capable of inhibiting Fbn-bound thrombin. Thrombin exosites I and II are hypothesized to play different roles in these processes. Exosite I binds HCII and PAI-1 directly, whereas exosite II - heparin binding may modulate HCII and PAI-1 turnover. These steps are absent in the T - AT reaction. DS bound outside exosite II is hypothesized to act as template for inhibition by HCII of exosite ll-blocked thrombin, meizothrombin (MzT), and MzT(desFI). The identity of this site; the HCII and PAI-1 substrate pathways; the mechanisms of DS- selective inhibition of Fbn-bound thrombin by HCII, and of fibrinogen (Fbg) and Fbn regulation of thrombin inhibition by PAI-1 are all unknown. The studies will resolve these significant gaps, by using fluorescence equilibrium binding, steady-state and rapid kinetics with native thrombin, HCII and PAI-1, and specific loss- of-function mutants. They will test the hypotheses: that the exosite roles in the GAG-catalyzed thrombin inactivation mechanisms by HCII, PAI-1 and AT are distinctly different; that GAG binding outside exosite II on thrombin mediates inhibition by HCII; and that Fbg and Fbn regulate thrombin inhibition by these serpins differentially. Specific aims are: (1) To quantitate binding and chemical steps in the sequence of molecular events in the GAG-catalyzed thrombin inactivation and substrate pathways of HCII and PAI-1, compared to AT; (2) Tocharacterize the DS-binding site outside exosite II in thrombin and MzT, and its role in thrombin and MzT inhibition; and (3) To determine the contributions of Fbg and Fbn binding to exosite I and GAGs in thrombin protection from HCII, PAI-1, and AT. These mechanism-based studies are relevant to understanding the selective, localized regulation of thrombin activity by HCII and PAI-1, and serpin turnover, in arterial clots. They may facilitate development of novel anticoagulants based on HCII and DS specifically targeted to arterial thrombosis.

长期目标是确定蛇蛋白抑制凝血酶(T)的分子机制，