SUBSTRUCTURE OF HUMAN VONWILLEBRAND-FACTOR
SUBSTRUCTURE OF HUMAN VONWILLEBRAND-FACTOR
复制标题
DOI：
10.1172/jci112129
复制
发表时间：
1985-01-01
影响因子：
15.9
通讯作者：
MCKEE, PA
中科院分区：
文献类型：
--
作者：
FOWLER, WE;FRETTO, LJ;MCKEE, PA
使用电子显微镜，我们已经可视化的人血管性血友病因子（vWf）纯化的两种不同的方法的子结构。vWf多聚体，其表现为长度变化高达2 μ m的柔性链，由通过二硫键以端对端方式线性聚合的二聚体单元（原聚体）组成。小多聚体（例如，一聚体、二聚体和三聚体）表明每个原聚体由两个大的球状末端结构域（22 × 10 - 25）组成。6.5 nm）连接到一个小的中心节点（6.4 × 6.5nm）。3.4 nm）通过两个柔性棒域，每个域34 nm长，直径约2nm。当完全伸展时，原聚体的长度为120 nm。在通过新的两步程序从新鲜血浆中快速纯化的vWf分子和从冻干的中等纯度因子VIII/vWf浓缩物中纯化的vWf分子中均观察到这些相同的结构特征。通过凝胶电泳观察到的240，000-mol wt亚基在vWf完全还原后明显含有杆状结构域和球状结构域，并且对应于原聚体的一半。两个亚基是二硫键连接的，可能在它们的羧基末端附近，以形成原聚体;氨基末端球状末端中的二硫键连接启动子以形成vWf多聚体。vWf多聚体链具有至少两种形态上不同类型的末端，其可由在形成大的线性聚合物后球状结构域中的蛋白水解裂解产生。除了释放大小和形状相似的片段的重复原聚体单位，vWf的任何制剂的血浆降解减少了多聚体的大小，但没有检测到的影响内部原聚体的亚结构。
Using electron microscopy, we have visualized the substructure of human von Willebrand factor (vWf) purified by two different approaches. vWf multimers, which appear as flexible strands varying in length up to 2 .mu.m, consist of dimeric units (protomers) polymerized linearly in an end-to-end fashion through disulfide bonds. Examination of small multimers (e.g., one-mers, two-mers, and three-mers) suggests that each protomer consists of two large globular end domains (22 .times. 6.5 nm) connected to a small central node (6.4 .times. 3.4 nm) by two flexible rod domains each .apprx. 34 nm long and .apprx. 2 nm in diameter. The protomer is 120 nm in length when fully extended. These same structural features are seen both in vWf molecules that were rapidly purified from fresh plasma by a new two-step procedure and in those purified from lyophilized intermediate-purity Factor VIII/vWf concentrates. The 240,000-mol wt subunit observed by gel electrophoresis upon complete reduction of vWf apparently contains both a rod domain and a globular domain and corresponds to one half of the protomer. Two subunits are disulfide-linked, probably near their carboxyl termini, to form the protomer; disulfide bonds in the amino-terminal globular ends link promoters to form vWf multimers. The vWf multimer strands have at least two morphologically distinct types of ends, which may result from proteolytic cleavage in the globular domains after formation of large linear polymers. In addition to releasing fragments that were similar in size and shape to the repeating protomeric unit, plasmic degradation of either preparation of vWf reduced the size of multimers, but had no detectable effect on the substructure of internal protomers.