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Molecular Basis of Blood Coagulation Regulation

凝血调节的分子基础

基本信息

批准号：
7819176
负责人：
Steven T. Olson
金额：
$ 0.72万
依托单位：
UNIVERSITY OF ILLINOIS AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-06-08 至 2009-10-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7819176
关键词：
Affect Amino Acids Angiogenesis Inhibitors Anticoagulants Antithrombin III Antithrombins Autolysis Binding Binding Sites Blood Clot Blood Proteins Blood coagulation Burial Cleaved cell Coagulation Process Complex Docking Elements Endothelial Cells Engineering Epitopes Event Factor IXa Factor Xa Family Generations Glycosaminoglycans Goals Heating Hemostatic function Heparan Sulfate Proteoglycan Heparin Heparin Binding Heparitin Sulfate Inorganic Sulfates Length Link Malignant Neoplasms Maps Mediating Molecular Molecular Conformation Peptide Hydrolases Physiological Protease Inhibitor Proteolysis Reaction Regulation Role S cerevisiae SWI3 protein Series Serpins Signal Transduction Site Specificity Structure Testing Unspecified or Sulfate Ion Sulfates Vertebrates antitumor drug base beta pleated sheet cardiovascular disorder prevention design improved mimetics novel receptor

项目摘要

The serpin family coagulation protease inhibitor, antithrombin and its glycosaminoglycan activators, heparin and heparan sulfate, comprise a key anticoagulant mechanism which is essential for maintaining hemostasis in vertebrates. Intriguingly, antithrombin has been recently shown to possess antiangiogenic and antitumor functions whose physiologic role remains to be determined. To advance our long-term goal of elucidating the molecular mechanisms by which antithrombin carries out its physiologically relevant functions, we propose to pursue three specific aims: 1) We have previously shown that the molecular determinants which mediate the specificity of heparin-activated antithrombin for blood clotting proteases reside both in an exposed reactive center loop of the serpin and in exosite regions outside the loop. We propose to map these exosite regions on antithrombin and on factor Xa and factor IXa and determine the mechanism by which the exosites mediate heparin rate enhancement of antithrombin reactions with the proteases; 2) Antithrombin circulates in an unusual low-activity conformation in which the reactive loop is partially buried in beta-sheet A, but is induced by heparin into a high-activity conformation resembling that of other serpins in which the reactive loop is expelled from the sheet. We propose to identify the molecular determinants of this reactive loop conformational switch and delineate the sequence of molecular events in the heparin binding site which trigger the conformational switch; 3) Antithrombin expresses a potent antiangiogenic activity when it undergoes conformational changes which occur spontaneously or are induced by cleavage in the reactive loop and which result in the burial of the reactive loop into beta-sheet A. We will determine the structural basis for the antiangiogenic activity of cleaved, latent and a novel prelatent form of antithrombin. The role of specific endothelial cell binding sites in this activity and whether these binding sites involve a protein receptor and/or specific domains of a heparan sulfate proteoglycan will be determined. The proposed studies are expected to provide increased understanding at the molecular level of the function of a key natural anticoagulant and antiangiogenic blood protein. This understanding is expected to facilitate the rational design of a new generation of anticoagulant and antitumor drugs for the treatment and prevention of cardiovascular diseases and cancer.

丝氨酸家族凝血酶抑制物抗凝血酶及其糖胺多聚糖激活剂肝素和硫酸乙酰肝素，构成了维持止血所必需的关键抗凝机制在脊椎动物中。有趣的是，抗凝血酶最近被证明具有抗血管生成和抗肿瘤的作用。生理作用尚待确定的功能。为了推进我们的长期目标，澄清抗凝血酶执行其生理相关功能的分子机制，我们建议追求三个具体目标：1)我们之前已经证明，调节肝素激活的抗凝血酶对凝血蛋白水解酶的特异性在蛇针的中心环和在环外的外区。我们建议绘制这些外星区域的地图抗凝血酶及其对凝血因子Xa和凝血因子IXa的影响介导肝素率提高抗凝血酶与酶的反应；2)抗凝血酶在一种不寻常的低活性构象，其中反应环部分埋在β-折叠A中，但由肝素诱导形成类似于其他蛇类的高活性构象，其中的反应循环将从板材中排除。我们建议确定这个反应环的分子决定因素构象转换和描绘在肝素结合部位的分子事件序列触发构象转换；3)当抗凝血酶表达出强大的抗血管生成活性时构象变化的经历自发发生的构象变化或由反应中的裂解引起的环，这导致反应环被埋入Beta-Sheet A。我们将确定结构裂解、潜伏和一种新型潜伏期抗凝血酶的抗血管生成活性基础。的作用这种活性中的特定内皮细胞结合部位以及这些结合部位是否涉及蛋白质受体和/或硫酸乙酰肝素蛋白多糖的特定结构域将被确定。建议进行的研究包括有望在分子水平上增加对关键天然蛋白功能的理解抗凝剂和抗血管生成血液蛋白。这一理解有望促进理性的新一代抗凝和抗肿瘤药物的设计心血管疾病和癌症。