Fibrin(ogen) Structure and Interactions

描述（由申请人提供）：纤维蛋白原（340 kDa）是一种多功能血浆蛋白，激活后可自发聚合形成纤维蛋白凝胶。纤维蛋白防止血管损伤时的血液流失，并在伤口愈合和其他生理和病理过程中作为各种细胞粘附、迁移和增殖的临时基质。纤维蛋白原以可控的方式聚合和降解并粘附在不同细胞上的能力使其成为一种理想的生物粘合剂（纤维蛋白密封剂），已越来越多地用于许多外科应用，用于止血、组织胶合、生物活性物质的输送等。更好地理解纤维蛋白依赖过程的机制和更有效地应用纤维蛋白密封剂需要对这种复杂分子的结构和相互作用有全面的了解。最近的研究建立了大约三分之二分子的高分辨率结构。本应用程序的第一个目的是完成剩余区域的高分辨率结构，并进一步阐明纤维蛋白原转化为纤维蛋白时的构象变化。我们最近发现，纤维蛋白原α - ac结构域与纤溶酶原、tPA和载脂蛋白(a)有高亲和力的相互作用，表明它们参与纤维蛋白溶解和动脉粥样硬化的形成。第二个目标是描述这些相互作用的特征，并阐明它们在这些过程的调节中的作用。其他纤维蛋白（原）区域，γ -模块和β -结构域，与白细胞和内皮细胞上的受体的相互作用被证明可以刺激炎症和血管生成。第三和第四个目标侧重于进一步建立这些相互作用的机制。这些目标将通过有限的蛋白水解和重组技术制备各种纤维蛋白（原）结构域及其组合，并通过生物化学和生物物理方法研究它们的结构和相互作用来实现。这些研究将产生基础知识，将对理解和控制上述纤维蛋白（原）依赖过程的能力产生影响。它们还将有助于开发具有理想性能的改良纤维蛋白密封剂。

DESCRIPTION (provided by applicant): Fibrinogen (340 kDa) is a multifunctional plasma protein that after activation spontaneously polymerizes to form a fibrin gel. Fibrin prevents the loss of blood upon vascular injury and serves subsequently as a provisional matrix on which various cell types adhere, migrate and proliferate during wound healing and other physiological and pathological processes. The ability of fibrinogen to polymerize and degrade in a controllable fashion and to adhere to different cells makes it an ideal bioadhesive (fibrin sealant) that has been used increasingly in numerous surgical application for arrest of bleeding, gluing of tissues, delivery of bioactive substances, etc. Better understanding of the mechanisms underlying fibrin-dependent processes and more effective application of fibrin sealant require comprehensive knowledge of the structure and interactions of this complex molecule. Recent studies established a high resolution structure of about two-thirds of the molecule. The first aim of this application is to complete the high-resolution structure of the remaining regions and to further clarify conformational changes upon conversion of fibrinogen to fibrin. Our recent discoveries that fibrinogen alphaC-domains interact with high affinity with plasminogen, tPA and apo(a) suggest their involvement in fibrinolysis and atherogenesis. The second aim is to characterize these interactions and to clarify their role in regulation of these processes. Interactions of the other fibrin(ogen) regions, gamma-modules and the betaN-domains, with receptors on leukocytes and endothelial cells was shown to stimulate inflammation and angiogenesis. The third and fourth aims focus on further establishing the mechanisms of these interactions. These aims will be accomplished by preparation of various fibrin(ogen) domains and combinations thereof by limited proteolysis and recombinant techniques, and studying their structures and interactions by biochemical and biophysical methods. These studies will generate basic knowledge that will have an impact on the understanding of and ability to control the above mentioned fibrin(ogen)-dependent processes. They will also contribute to the development of improved fibrin sealants with desirable properties.