STRUCTURAL STUDIES OF BLOOD CLOTTING PROTEINS

本研究项目的目标是获得结构 关于纤维蛋白和纤维蛋白原及其相互作用的信息 以阐明凝血的分子机制。 主要目标是研究纤维蛋白的结构。 凝块及其组装机制和凝块浓度的测定 更高分辨率的纤维蛋白原分子结构。 未染色的、冷冻的、水合的纤维纤维将被HIGH检查 分辨率，低剂量电子显微镜。比钙 纤维将用电子探针进行测量。的性质 纤维的侧向聚集将用电子来研究。 显微镜。钙离子浓度、碳水化合物的影响 含量和几种血小板蛋白的聚集将被 下定决心。纤维蛋白单体沉淀形成的纤维 将通过电子显微镜进行检查。量化 将对纤维的扭曲程度进行测量，以评估 可能的直径限制机制。电子显微镜 将用于研究纤维的分枝、溶解 纤溶酶的凝块，以及排列的有序程度 凝块中的纤维。阿尔法oc结构域的性质，从 修饰后的纤维蛋白原，将用电子显微镜进行研究 单个纤维蛋白原和纤维蛋白分子的显微镜。我们的 最近关于分子形状的三维模型将 用于获得X射线结晶学的初始物相 已收集的数据；这些阶段将通过使用 非晶态的双重对称性平均化和溶剂化 变平了。最近生长的人类纤维蛋白原晶体和 将对片段D进行表征。的长期目标之一 这项研究旨在将这些结构研究的结果与 生化、生理和临床工作在同一地区。 复杂的凝血/纤溶系统在许多情况下是不平衡的 病理条件。；发展出更有效和更具体的 方法来控制这些过程，有必要了解 所涉及蛋白质的分子结构和相互作用。

The objective of this research project is to obtain structural information about fibrin and fibrinogen and their interactions in order to elucidate aspects of the molecular mechanism of clotting. Major goals are the investigation of the structure of the fibrin clot and the mechanism of its assembly and the determination of the structure of he fibrinogen molecule at higher resolution. Unstained, frozen, hydrated fibrin fibers will be examined by high resolution, low dose electron microscopy. The specific calcium to fibers will be measured by electron microprobe. The nature of the lateral aggregation of fibers will be explored by electron microscopy. The influence of calcium concentration, carbohydrate content and several platelet proteins on aggregation will be determined. Fibers formed by precipitation of fibrin monomer will be examined by electron microscopy. Quantitative measurements of the twisting of fibers will be made to evaluate a possible mechanism for diameter limitation. Electron microscopy will be used to study the branching of fibers, the dissolution of the clot by plasmin, and the extent of order in the arrangement of fibers in a clot. The nature of the alpha oc domain, missing from the modified fibrinogens, will be investigated by electron microscopy of individual fibrinogen and fibrin molecules. Our recent three-dimensional model for the shape of the molecule will be used to obtain initial phases for the X-ray crystallographic data that has been collected; these phases will be refined by use of non-crystallographic two-fold symmetry averaging and solvent flattening. Recently grown crystals of human fibrinogen and fragment D will be characterized. One of the long term goals of this research is to relate the results of these structural studies to biochemical, physiological and clinical work in the same area. The complex clotting/fibrinolytic system is unbalanced in many pathological conditions.; to develop more effective and specific methods to control these processes, it is necessary to understand the molecular structures and interactions of the proteins involved.