Structure and Function of Protein-Membrane Interactions in Blood Clotting

描述（由申请人提供）：血液凝固的几乎每个步骤都需要在膜表面组装多种蛋白质，但在分子水平上对血液凝固中的蛋白质-膜相互作用仍知之甚少。我们正在使用新的高分辨率技术，包括魔角旋转固态核磁共振（SSNMR）来探测凝血蛋白与磷脂表面相互作用的机制，以及膜组成的变化如何调节凝血反应。我们研究的主要焦点是组织因子和因子VIIa的膜结合复合物，这是一种负责触发健康和疾病中血液凝固的双亚基酶。目的1将描绘，在原子分辨率，在结构和动力学的变化的PS-丰富的膜结构域中的Ca 2+的存在下，并将检查磷脂酰丝氨酸，磷脂酰胆碱和磷脂酰乙醇胺的作用，在配置膜，以支持高亲和力结合的凝血因子。目的2将研究磷脂-磷脂相互作用在增强膜表面凝血反应中的作用。目的3将描绘当凝血蛋白结合到双层时诱导的脂质环境/构象。目的4解决组织因子在膜表面的结构，并确定组织因子与配体相互作用时的构象变化。总之，这些研究将提供有价值的新见解的作用，膜表面在血液凝固，在原子尺度的分辨率。

DESCRIPTION (provided by applicant): Almost every step in blood coagulation requires assembly of multiple proteins on membrane surfaces, yet protein-membrane interactions in blood clotting remain poorly understood at the molecular level. We are using new, high-resolution technologies including magic-angle spinning solid-state NMR (SSNMR) to probe the mechanisms by which blood clotting proteins interact with phospholipid surfaces, and how changes in membrane composition regulate clotting reactions. The primary focus of our studies is the membrane-bound complex of tissue factor and factor VIIa, the two-subunit enzyme responsible for triggering blood clotting in health and disease. Aim 1 will delineate, at atomic resolution, the changes in structure and dynamics of PS- rich membrane domains in the presence of Ca2+, and will examine the roles of phosphatidylserine, phosphatidylcholine and phosphatidylethanolamine in configuring the membrane to support high affinity binding of clotting factors. Aim 2 will investigate the role of phospholipid-phospholipid interactions in enhancing blood clotting reactions on membrane surfaces. Aim 3 will delineate the lipid environments/conformations induced when clotting proteins bind to bilayers. Aim 4 will solve the structure of tissue factor on the membrane surface and identify conformational changes in tissue factor when it interacts with ligands. Together these studies will provide valuable new insights into the role of the membrane surface in blood clotting, at atomic-scale resolution.