Role of the N- and C-terminal actin-binding domains of gelsolin in barbed filament end capping.
Role of the N- and C-terminal actin-binding domains of gelsolin in barbed filament end capping.
复制标题
凝溶胶蛋白的 N 端和 C 端肌动蛋白结合域在倒刺细丝封端中的作用。
DOI：
10.1021/bi00102a027
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发表时间：
1991
期刊：
影响因子：
2.9
通讯作者：
Bryan,J
中科院分区：
文献类型：
--
作者：
Weber,A;Pring,M;Lin,SL;Bryan,J
Department of Biochemistry and Biophysics and Department of Physiology，University of Pennsylvania School of Medicine，Philadelphia，Pennsylvania 19104，and Department of Cell Biology，Baylor College of Medicine，Houston，Texas 77030 Received April 23，1991; Revised Mandarin pt Received July 8，1991摘要：凝溶胶蛋白是一种二价钙离子调节的肌动蛋白结合蛋白，能切断、成核和覆盖纤维。为了更好地理解加帽机制，我们研究了N-和C-末端凝溶胶蛋白片段，14 NT和41 CT，其中每个片段都包含一个单一的功能性肌动蛋白结合位点。在凝溶胶蛋白和有倒刺的丝状体末端之间测量到的非常紧密的结合需要凝溶胶蛋白大大降低末端肌动蛋白从该末端的解离速率常数。可以解释所观察到的解离减少的机制是凝溶胶蛋白连接两个肌动蛋白单体，使得它们作为二聚体解离得更慢。然而，这不是唯一的机制，因为，如图所示，14 NT和41 CT，具有单个肌动蛋白结合位点的片段，降低了加帽末端肌动蛋白分子的解离速率。观察结果表明，这些片段诱导肌动蛋白单体的构象变化，从而增加亲和力或改变末端肌动蛋白-肌动蛋白键的动力学。现有的数据认为，加强终端肌动蛋白肌动蛋白键。
Department of Biochemistry and Biophysics and Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, andDepartment of Cell Biology, Baylor College of Medicine, Houston, Texas 77030 Received April 23, 1991; Revised Manuscript Received July 8, 1991 abstract: Gelsolin is a bivalent Ca2+-modulated actin-binding protein that severs, nucleates, and caps filaments. In order to gain a better understanding of the capping mechanism we have studied N-and C-terminal gelsolin fragments, 14NT and 41CT, each of which contains a single functional actin-binding site. The very tight binding measured between gelsolinand the barbed filament end requires gelsolin to greatly decrease the dissociation rate constant of the terminal actin from this end. A mechanism that could account for the observed decrease in dissociation is one in which gelsolin links two actin monomers so that they dissociate more slowly as a dimer. This cannot be the only mechanism, however, since, as shown here, 14NT and 41CT, fragments with single actin-binding sites, decrease thedissociation rate of the capped terminal actin molecule. The observations suggest that these fragments induce a conformational change in the actin monomer that either increases the affinity or alters the kinetics of the terminal actin-actin bond. The available data argue for strengthening of the terminal actin-actin bond.