Supramolecular forms of actin from amoebae of Dictyostelium discoideum.
Supramolecular forms of actin from amoebae of Dictyostelium discoideum.
复制标题
来自盘基网柄菌变形虫的超分子形式肌动蛋白。
DOI：
10.1016/s0021-9258(19)40970-8
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发表时间：
1975
期刊：
影响因子：
--
通讯作者：
R. Cooke
中科院分区：
文献类型：
--
作者：
J. Spudich;R. Cooke
从盘状网柄藻的变形虫中纯化的肌动蛋白在加入KCl后在24度下聚合成细丝，如通过232 nm处的光密度变化和电子显微镜所判断的。该超分子组装的形成速率和程度以及组装的最佳KCl浓度（0.1 M）与横纹肌肌动蛋白的形成速率和程度相似。表观平衡常数为单体-聚合物的转变是1.3 μ M的Dictyosteoprotein和肌肉肌动蛋白。虽然高度纯化的网骨藻肌动蛋白单体组装成单个肌动蛋白丝类似于肌肉肌动蛋白，但观察到网骨藻肌动蛋白而不是肌肉肌动蛋白在10 mM CaCl 2中组装成二维网。网骨藻肌动蛋白还形成直径为0.1 μ m的丝束，并在5 mM MgCl 2存在下组装。这些束形成部分纯化的Dictyosteoblastin肌动蛋白制剂，但不是从高度纯化的制剂，这表明它们的形成可能取决于另一种成分的存在。这些肌动蛋白束在体外重建类似于在许多非肌肉细胞中通过显微镜原位发现的含肌动蛋白束。
Actin purified from amoebae of Dictyostelium discoideum polymerizes into filaments at 24 degrees upon addition of KCl, as judged by a change in optical density at 232 nm and by electron microscopy. The rate and extent of formation of this supramolecular assembly and the optimal KCl concentrations (0.1 M) for assembly are similar to those of striated muscle actin. The apparent equilibrium constant for the monomer-polymer transition is 1.3 muM for both Dictyostelium and muscle actin. Although assembly of highly purified Dictyostelium actin monomers into individual actin filaments resembles that of muscle actin, Dictyostelium actin but not muscle actin was observed to assemble into two-dimensional nets in 10 mM CaCl2. The Dictyostelium actin also forms filament bundles which are 0.1 mum in diameter and which assemble in the presence of 5 mM MgCl2. These bundles formed from partially purified Dictyostelium actin preparations but not from highly purified preparations, suggesting that their formation may depend on the presence of another component. These actin bundles reconstituted in vitro resemble the actin-containing bundles found in situ by microscopy in many non-muscle cells.