An actin-depolymerizing protein (depactin) from starfish oocytes: properties and interaction with actin.
An actin-depolymerizing protein (depactin) from starfish oocytes: properties and interaction with actin.
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来自海星卵母细胞的肌动蛋白 - 脱聚合蛋白（Depactin）：特性和与肌动蛋白的相互作用。
DOI：
10.1083/jcb.97.5.1612
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发表时间：
1983-11
影响因子：
7.8
通讯作者：
Mabuchi, I
中科院分区：
文献类型：
--
作者：
Mabuchi, I
研究了海星卵母细胞肌动蛋白解聚蛋白的理化性质及其与肌动蛋白的相互作用。这种蛋白质被称为depactin，在生理条件下以单体形式存在。天然蛋白质的分子量约为20，000，变性蛋白质的分子量约为17，000。该蛋白的Glu + Asp/Lys + Arg摩尔比为1.55。变性的depactin的表观pI约为6。肌动蛋白聚合的程度被depactin的存在降低;然而，聚合的速率似乎被加速，如在238 nm处用荧光光度法测量的。这种效应被解释为表明，depactin将新形成的细丝切割成小片段，从而增加了加入单体的细丝末端的数量。聚合的肌动蛋白的表观临界浓度，如通过粘度计或流动双折射测量所确定的，通过depactin以浓度依赖性方式的存在而增加。提高溶液的pH值不会逆转depactin的作用。通过使用水溶性碳二亚胺的交联实验，相互作用的肌动蛋白和脱肌动蛋白的摩尔比估计为1：1。Depactin通过肌动蛋白与DNase I-Sepharose柱结合，并用0.6 M KCl或0.6 M KI选择性洗脱。使用该柱估计肌动蛋白和去肌动蛋白之间的缔合常数为2-3 X 10（6）M-1。卵母细胞提取物的高速上清液中的脱肌动蛋白的含量被确定为1%;这可以作用于上清液中大约63%的肌动蛋白。
Physico-chemical properties and interaction with actin of an actin- depolymerizing protein from mature starfish oocytes were studied. This protein, which is called depactin, exists in a monomeric form under physiological conditions. Its molecular weight is approximately 20,000 for the native protein and approximately 17,000 for denatured protein. The Glu + Asp/Lys + Arg molar ratio of this protein is 1.55. The apparent pl of the denatured depactin is approximately 6. The extent of actin polymerization is reduced by the presence of depactin; however, the rate of polymerization seems to be accelerated as measured spectrophotometrically at 238nm. This effect is interpreted to indicate that depactin cut the newly formed filaments into small fragments, thereby increasing the number of the filament ends to which monomers are added. The apparent critical concentration of actin for polymerization, as determined by viscometry or flow birefringence measurement, is increased by the presence of depactin in a concentration-dependent manner. Raising the pH of the solution does not reverse the action of depactin. The molar ratio of actin and depactin, which interact with each other, is estimated to be 1:1 by means of a cross-linking experiment using a water-soluble carbodiimide. Depactin binds to a DNase I-Sepharose column via actin and is selectively eluted with 0.6 M KCl or 0.6 M Kl. The association constant between actin and depactin is estimated, using the column, to be 2-3 X 10(6) M-1. The content of depactin in the high-speed supernatant of the oocyte extract is determined to be 1%; this can act upon approximately 63% of the actin in the supernatant.