Fowler W E, Hantgan R R, Hermans J, Erickson H P
Proc Natl Acad Sci U S A. 1981 Aug;78(8):4872-6. doi: 10.1073/pnas.78.8.4872.
We identified the two-stranded fibrin protofibril and studied its structure in electron micrographs of negatively stained specimens. Based on these images and on considerations of symmetry, we constructed a model of the protofibril in which the two strands of trinodular fibrin molecules are related by a two-fold screw axis between the strands and two-fold axes perpendicular to them. The two strands are held together by staggered lateral contacts between the central nodules of one strand and outer nodules of the other. The molecules within a strand are joined by longitudinal contacts between outer nodules. This interpretation of the structure of protofibrils is supported by images of trimer complexes whose preparation and structure are described here, in which the central nodule of a fibrin monomer is attached to the crosslinked outer nodules of two other molecules. We conclude that the association of protofibrils to form thicker fibers must involve a second type of lateral contact, probably between outer nodules of adjacent, in-register strands. In total, we identify three intermolecular contacts involved in the polymerization of fibrin.
我们鉴定出了双链纤维蛋白原纤维，并在负染标本的电子显微照片中研究了其结构。基于这些图像以及对称性方面的考虑，我们构建了原纤维的模型，其中三结节纤维蛋白分子的两条链通过链间的二重螺旋轴以及垂直于它们的二重轴相关联。两条链通过一条链的中央结节与另一条链的外侧结节之间的交错侧向接触而结合在一起。链内的分子通过外侧结节之间的纵向接触相连。三聚体复合物的图像支持了对原纤维结构的这种解释，本文描述了其制备方法和结构，其中纤维蛋白单体的中央结节附着于另外两个分子的交联外侧结节上。我们得出结论，原纤维缔合形成更粗的纤维必定涉及第二种侧向接触类型，可能是相邻、对齐链的外侧结节之间的接触。我们总共鉴定出了三种参与纤维蛋白聚合的分子间接触。
