STRUCTURAL STUDIES ON FIBRINOGEN AND FIBRIN

这个项目的长期目标仍然是实现原子- 人纤维蛋白原分子的水平结构及其分子生物学意义 在转化为纤维蛋白凝块的过程中发生的相互作用。 为此，我们建议解决几个元素的X射线结构 人类纤维蛋白原的主要片段，从片段D开始，然后 继续讨论因子XIII-被称为D-二聚体的部分，然后 片段E，复合体“D2E”，最后是一些来自 其他生物。我们已经从水晶石收集了数据 片段D的分辨率为3.5A，并且具有几个有希望的同构 手中有重金属衍生品。我们目前正在尝试对数据进行阶段化 并确定可解释的电子密度图。我们也有水晶 片段D与Gly-Pro-Arg-Pro-酰胺络合。值得注意的是，这些 与(自由的)D处于不同的空间群中，并且具有不同的单位 手机。单元格太大了，我们可能不得不从 这些晶体是在同步加速器的设施里。我们计划解决这个结构 一旦知道(自由的)D结构，通过分子置换。我们也 手中有D-二聚体晶体。所有这些研究应该揭示出许多 纤维蛋白原结构的细节以及分子如何在 纤维蛋白形成的早期步骤。基因的结构基础 有缺陷的人类纤维蛋白原也将得到澄清。我们还计划 继续我们对多肽抗聚合体的长期研究，更好的设计 根据所确定的结构是可能的。最后，在这里 是这些结构和其他蛋白质之间的进化联系 (例如，Tenascin)，我们计划利用它。

The long-term goal of this project remains the attainment of an atomic- level structure of the human fibrinogen molecule and the elucidation of the interactions that occur during its transformation into fibrin clots. To this end, we are proposing to solve the X-ray structures of several major fragments of human fibrinogen, beginning with fragment D, and then continuing on to the factor XIII-crosslinked moiety known as D-dimer, then fragment E, the complex "D2E", and finally, some small fibrinogens from other creatures. We have already collected data from the crystals of fragment D at a resolution of 3.5 A and have several promising isomorphous heavy metal derivatives in hand. We are currently trying to phase the data and determine an interpretable electron density map. We also have crystals of fragment D complexed with Gly-Pro-Arg-Pro-amide. Significantly, these are in a different space group from the (free) D and have a different unit cell. The unit cell is so large that we may have to collect data from these crystals at a synchrotron facility. We plan to solve the structure by molecular replacement once the (free) D structure is known. We also have the D-dimer crystals in hand. All of these studies should reveal many details of fibrinogen structure and how the molecules interact in the early steps of fibrin formation. The structural basis of genetically defective human fibrinogens will also be clarified. We also plan to continue our longstanding study on peptide antipolymerants, better designs being possible in the light of the determined structures. Finally, there are evolutionary connections between these structures and other proteins (e.g., tenascin) that we plan to exploit.