Mosesson M W, DiOrio J P, Siebenlist K R, Wall J S, Hainfeld J F
Sinai Samaritan Medical Center, University of Wisconsin Medical School, Milwaukee 53233.
Blood. 1993 Sep 1;82(5):1517-21.
Fibrin molecules polymerize to double-stranded fibrils by intermolecular end-to-middle domain pairing of complementary polymerization sites, accompanied by fibril branching to form a clot network. Mass/length measurements on scanning transmission electron microscopic images of fibrils comprising branch points showed two types of junctions. Tetramolecular junctions occur when two fibrils converge, creating a third branch with twice the mass/length of its constituents. Newly recognized trimolecular junctions have three fibril branches of equal mass/length, and occur when an extraneous fibrin molecule initiates branching in a propagating fibril by bridging across two unpaired complementary polymerization sites. When trimolecular junctions predominate, clots exhibit nearly perfect elasticity.
纤维蛋白分子通过互补聚合位点的分子间端对中结构域配对聚合成双链纤维，同时伴有纤维分支形成凝块网络。对包含分支点的纤维的扫描透射电子显微镜图像进行质量/长度测量，发现有两种类型的连接。当两条纤维汇聚时会出现四分子连接，形成第三条分支，其质量/长度是其组成部分的两倍。新发现的三分子连接有三个质量/长度相等的纤维分支，当一个外来纤维蛋白分子通过跨越两个未配对的互补聚合位点在正在延伸的纤维中引发分支时就会出现这种情况。当三分子连接占主导时，凝块表现出近乎完美的弹性。
