MOLECULAR BASIS OF BLOOD COAGULATION REGULAT

描述：(改编自调查人员摘要) 这项提议是为了提供对血液凝结如何 蛋白水解酶由血浆丝氨酸蛋白酶抑制物调节， 抗凝血酶及其糖胺聚糖辅助因子，肝素，在分子 水平。具体目的是：1)阐明结构决定因素 抗凝血酶的靶标蛋白的特异性，并确定如何 这种特异性被表达出来；ii)将肝素结合位点定位在 抗凝血酶和确定与肝素有关的分子事件 抗凝血酶的激活；以及iii)确定 凝血酶和凝血因子Xa的抗凝血酶抑制作用受 这些酶在生理复合体中的结合，从而定位它们的 行动，并阐明这种抑制对边界的后果 蛋白水解酶。这些研究将利用定点突变来绘制 抗凝血酶与凝血酶相互作用的功能位点 蛋白酶和肝素，并检验定义这种关系的假设 抗凝血酶结构与功能之间的关系。热力学和动力学 将使用方法来量化抗凝血酶之间的相互作用， 蛋白水解酶、肝素和其他调节成分及其作用 这些相互作用上的突变。这些研究预计将提供 抗凝血酶S抗凝血酶的结构基础新探 凝血酶，其稳定捕获凝血酶的能力 失活的复合体及其被肝素激活。他们应该进一步 阐述一种新的凝血酶动态调节模型 蛋白水解酶与其受体作用部位结合的抗凝血酶 在这些部位被抗凝血酶抑制，并伴随着释放 抑制蛋白水解酶。这些研究也应该提供一个合理的基础 用于设计重组抗凝血酶或合成肝素 量身定制的抗血栓活性。

DESCRIPTION: (adapted from investigator's abstract) The long-term goal of this proposal is to provide a complete understanding of how blood clotting proteinases are regulated by the plasma serine proteinase inhibitor, antithrombin, and its glycosaminoglycan cofactor, heparin, at the molecular level. The specific aims are: 1) to elucidate the structural determinants of the target proteinase specificity of antithrombin and to determine how this specificity is expressed; ii) to map the heparin binding site in antithrombin and to determine the molecular events involved in heparin activation of antithrombin; and iii) to determine the extent to which antithrombin inhibition of thrombin and factor Xa is modulated by the binding of these proteinases in physiologic complexes which localize their action and to elucidate the consequences of this inhibition on the bound proteinase. These studies will utilize site-directed mutagenesis to map the functional sites of antithrombin which mediate its interactions with proteinases and heparin and to test hypotheses which define the relationship between antithrombin structure and function. Thermodynamic and kinetic approaches will be used to quantitate the interactions between antithrombin, proteinases, heparin and other regulatory components and the effects of mutation on these interactions. These studies are anticipated to provide new insights into the structural basis of antithrombin s specificity for clotting proteinases, its ability to trap clotting proteinases in stable inactive complexes and its activation by heparin. They should further elaborate a new model of dynamic regulation of clotting proteinases by antithrombin in which proteinases bound to their receptor sites of action are inhibited by antithrombin at these sites with concomitant release of the inhibited proteinase. These studies should also provide a rational basis for the design of recombinant antithrombins or synthetic heparins with tailor-made antithrombotic activity.