Molecular investigations of antithrombin instability and heparin binding mechanism

血栓形成是影响大量人群的重要疾病。急性血栓发作的主要治疗是使用抗凝剂肝素。肝素发挥作用的效应分子是丝氨酸蛋白酶抑制剂，抗凝血酶。这种分子通过抑制执行凝血过程的蛋白酶来调节血液凝固。抗凝血酶从凝血蛋白酶的不良抑制剂转化为结合肝素的良好抑制剂。这为凝聚提供了一个控制点。抗凝血酶转化为非常好的凝血蛋白酶抑制剂的机制涉及到这种蛋白质结构的巨大变化。这些结构上的变化与抗凝血酶通过聚合过程变得无活性时发生的变化有关。已发现某些血栓患者抗凝血酶分子的稳定性和肝素亲和力发生变化，这构成了该疾病的潜在基础。我们希望通过制造模拟血栓患者分子的重组突变体，并对其与肝素和蛋白酶的相互作用及其在各种条件下的稳定性进行详细、复杂的分子分析，来研究抗凝血酶变异体突变影响的原因。此外，我们将设计抗凝血酶的重组突变体，我们相信这将稳定分子，并有可能作为治疗的改进补充。这一分析将为肝素和抗凝血酶的功能提供重要的见解，从而显著提高我们对凝血控制的理解。

Thrombosis is a significant disease affecting a large number of people. The primary treatment for episodes of acute thrombosis is administration of the anticoagulant, heparin. The effector molecule through which heparin carries out its action is the serine proteinase inhibitor, antithrombin. This molecule regulates blood clotting by inhibiting the proteinases which carry out this process. Antithrombin is converted from a poor inhibitor of coagulation proteases to a very good inhibitor on binding heparin. This provides a control point for coagulation. The mechanism by which antithrombin is converted to a very good inhibitor of coagulation proteases involves a large change in the structure of this protein. These changes in structure are linked to the changes which occur when antithrombin becomes inactive through the process of polymerisation. Certain patients with thrombosis have been found to have changes in both the stability and heparin affinity of their antithrombin molecules, which forms the underlying basis for the disease. We wish to study the reasons for the effects of mutations in the antithrombin variants by making recombinant mutants which mimic the molecules in the thrombotic patients and carrying out detailed, sophisticated molecular analyses of their interaction with heparin and proteases and their stability under various conditions. Additionally we will engineer recombinant mutants of antithrombin which we believe will stabilise the molecule and potentially act as an improved supplement for therapy. This analysis will provide important insights into the functioning of both heparin and antithrombin and thereby significantly improve our understanding of the control of coagulation.