CRYSTAL STRUCTURE OF FIBRINOGEN FRAGMENTS

纤维蛋白原是纤维蛋白的前体， 凝块组成。 它是一种大分子量糖蛋白 由两对三条不同的多肽链组成。 一 整个分子的高分辨率X射线结构还有待于 得到了 最近，我们确定了主要的结构， 人纤维蛋白原的蛋白水解片段，片段D，以及 来自因子XIII交联的人纤维蛋白的相应片段 （双D）。 我们还成功地使这两种物质共结晶 具有两种不同合成肽的实体， 在纤维蛋白原的片段E部分上发现的聚合球。 所有 我们已经能够获得七个不同的（但接近 相关的结构。 各种结构的分辨率范围 从2.9到2.3 E.发现了许多构象变化 对应于纤维蛋白原早期阶段的各个步骤， 纤维蛋白转化。 我们还有重要的复合晶体 称为“D2E”。“虽然晶体很小，但我们希望， 我们将能够收集足够高质量的数据， 片段E部分在分子水平上是明显的， 单独更换溶液。

Fibrinogen is the precursor of fibrin, the material of which blood clots are composed. It is a large molecular weight glycoprotein composed of two pairs of three non-identical polypeptide chains. A high resolution X-ray structure of the whole molecule has yet to be obtained. Recently, we determined the structures of the principal proteolytic fragment of human fibrinogen, fragment D, and also of the corresponding fragments from factor XIII crosslinked human fibrin (double-D). We have also managed to co-crystallize both of these entities with two different synthetic peptides that correspond to the polymerization knobs found on the fragment E part of fibrinogen. All told, we have been able to obtain seven different (but closely related) structures. The resolution of the various structures ranges from 2.9 to 2.3 E. A number of conformational changes have been found that correspond to various steps in the early stages of the fibrinogen to fibrin conversion. We also have crystals of the important complex known as "D2E." Although the crystals are small, it is our hope that we will be able to collect sufficient data of a high enough quality that the fragment E portion will be apparent with a molecular replacement solution alone.