Morphology of bovine fibrinogen monomers and fibrin oligomers.
Morphology of bovine fibrinogen monomers and fibrin oligomers.
复制标题
牛纤维蛋白原单体和纤维蛋白低聚物的形态。
DOI：
10.1016/0022-2836(81)90555-6
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发表时间：
1981
影响因子：
5.6
通讯作者：
R. Williams
中科院分区：
文献类型：
--
作者：
R. Williams
通过旋转阴影和负染色进行对比增强后，通过电子显微镜检查了牛纤维蛋白原分子和凝血酶诱导的纤维蛋白小低聚物。旋转阴影的分子，除了表现出众所周知的三结节结构，显示了相当均匀的宽度连接中央结节与终端突起的脊柱。在用甲酸铀酰或乙酸铀酰负染色的标本中，大多数分子具有轻微的S形构型，都具有相似的旋向性。棘明显突出，经常有轻微的中央隆起。末端突起呈明显的椭圆形，彼此平行，长尺寸与脊柱相邻部分的轴线倾斜约45 °。暴露后的纤维蛋白原分子的毫摩尔Ca 2+的中央隆起变得更加明显，每个终端突起的形式上的两个连续的，大小相等的球体。重要的方面是：分子全长45 nm;棘的长度和宽度31 nm × 3 nm;末端突起的长度和宽度9 nm × 4 nm; Ca 2+诱导的球体直径约4 nm。在纤维蛋白原溶液中加入微量凝血酶（并去除肉眼可见的凝块）的样本含有低聚物组装体，这些组装体足够小，可以分解为纤维蛋白亚基。它们由两条平行的链组成，并且彼此相似，因为它们的亚基数量相差不超过一个。低聚物的一条链中的元素似乎与另一条链中的元素结合，具有半分子交错重叠。它们保留了纤维蛋白原分子的长度。
Molecules of bovine fibrinogen and small oligomers of thrombin-induced fibrin have been examined by electron microscopy after contrast enhancement by rotary shadowing and by negative staining. Rotary-shadowed molecules, in addition to exhibiting the well-known trinodular structure, showed a spine of fairly uniform width connecting the central nodule with the terminal protrusions. In specimens negatively stained with uranyl formate or acetate most of the molecules had a gently sigmoidal configuration, all of like handedness. The spines were visibly prominent and frequently had a slight central bulge. The terminal protrusions appeared with a distinctly oblong shape and were oriented parallel to each other, with the long dimension tilted about 45 ° to the axis of the contiguous part of the spine. After exposure of the fibrinogen molecules to millimolar Ca2+the central bulge became more noticeable and each terminal protrusion took on the form of two contiguous, equal-sized spheres. Significant dimensions are: overall length of molecule, 45 nm; length and width of spine, 31 nm × 3 nm; length and width of terminal protrusions, 9 nm × 4 nm; diameter of Ca2+-induced spheres, ~ 4 nm.Specimens from fibrinogen solutions to which minute amounts of thrombin had been added (and the macroscopic clots removed) contained oligomeric assemblies that were small enough to be resolvable into their fibrin subunits. They consisted of two chains that were parallel and were similar to each other in that they never differed by more than one in their subunit number. The elements in one chain of an oligomer appeared to be bound to those of the other chain with a half-molecule staggered overlap. They retained the lengths they had as fibrinogen molecules.