Ikkai T, Kondo H
Aichi Prefectural University of Fine Arts, Nagakute, Japan.
IUBMB Life. 2000 Jan;49(1):77-9. doi: 10.1080/713803584.
The polymerization of actin induced by dilution has previously been reported, where a 1000-fold molar excess of ATP over actin resulted when actin was diluted to 4.0 microg/ml in low salt buffer A (0.1 mM ATP, 0.1 mM CaCl2, 2 mM Tris-HCl, pH 8.0, 5 mM 2-mercaptoethanol, 1 mM NaN3). Filaments formed by the addition of ATP to a 1000-fold molar excess over actin in buffer B (0.1 mM CaCl2, 2 mM Tris-HCl, pH 8.0, 1 mM NaN3) were then separated by gel-filtration. When ATP was removed from these filaments using Dowex-1, depolymerization occurred. Thus, the reversible polymerization induced by the dilution of actin or by addition of ATP can be ascribed to the binding of ATP at the low affinity site of actin.
先前已有报道称，肌动蛋白稀释可诱导其聚合，当肌动蛋白在低盐缓冲液A（0.1 mM ATP、0.1 mM CaCl2、2 mM Tris-HCl，pH 8.0、5 mM 2-巯基乙醇、1 mM叠氮化钠）中稀释至4.0微克/毫升时，ATP的摩尔量比肌动蛋白高1000倍。然后通过凝胶过滤分离在缓冲液B（0.1 mM CaCl2、2 mM Tris-HCl，pH 8.0、1 mM叠氮化钠）中添加比肌动蛋白摩尔量高1000倍的ATP所形成的细丝。当使用Dowex-1从这些细丝中去除ATP时，就会发生解聚。因此，肌动蛋白稀释或添加ATP所诱导的可逆聚合可归因于ATP在肌动蛋白低亲和力位点的结合。
