Hatano S, Owaribe K
Biochim Biophys Acta. 1979 Jul 25;579(1):200-15. doi: 10.1016/0005-2795(79)90099-0.
A factor termed Physarum actinin was isolated and partially purified from plasmodia of a myxomycete, Physarum polycephalum. When Physarum actinin was mixed with purified Physarum or rabbit striated muscle G-actin in a weight ratio of about 1 actinin to 9 actin and then the polymerization of G-actin induced, G-actin polymerized to the ordinary F-actin on addition of 0.1 M KCl. However, it polymerized to Mg-polymer on addition of 2 mM MgCl2. The reduced viscosity (etasp/C) of the Mg-polymer was 1.2 dl/g, about one-seventh of that of the F-actin (7.4 dl/g). The sedimentation coefficient of the Mg-polymer was 22.8 S, almost the same as that of the F-actin (29.4 S). The Mg-polymer showed the specific ATPase activity of the order of 1 . 10(-3) mumol ATP/mg actin per min. It was shown that Physarum actinin copolymerized with G-actin to form Mg-polymer on addition of 2 mM MgCl2. The molecular weights of Physarum actinin were about 90 000 in salt-free or slat solutions and 43 000 in a dodecyl sulfate solution. The range of salting out with ammonium sulfate was 50--65% saturation, which was different from that of Physarum actin (15--35% saturation). Physarum actinin did not interact with Physarum myosin or muscle heavy meromyosin. When the weight ratio of actinin to actin increased, the flow birefringence of the formed Mg-polymer decreased, and it became almost zero at the weight ratio of 1 actinin to 5 actin. ATPase activity reached the maximum level (2.2 . 10(-3) mumol ATP/mg actin per min) at the same ratio. On the addition of Physarum actinin to purified Physarum F-actin which had been polymerized on addition of 2 mM MgCl2 the viscosity decreased rapidly, suggesting that the F-actin filaments were broken in the smaller fragments or that they transformed to Mg-polymers. A factor with properties similar to Physarum actinin was isolated from acetone powder of sea urchin eggs.
从黏菌多头绒泡菌的原质团中分离并部分纯化了一种名为绒泡菌辅肌动蛋白的因子。当绒泡菌辅肌动蛋白与纯化的绒泡菌或兔横纹肌G -肌动蛋白按约1:9的重量比混合，然后诱导G -肌动蛋白聚合时，加入0.1M KCl后，G -肌动蛋白聚合成普通的F -肌动蛋白。然而，加入2mM MgCl₂后，它聚合成镁聚合物。镁聚合物的比浓黏度（ηsp/C）为1.2dl/g，约为F -肌动蛋白（7.4dl/g）的七分之一。镁聚合物的沉降系数为22.8S，与F -肌动蛋白（29.4S）几乎相同。镁聚合物的比ATP酶活性约为1×10⁻³ μmol ATP/（mg肌动蛋白·min）。结果表明，加入2mM MgCl₂后，绒泡菌辅肌动蛋白与G -肌动蛋白共聚形成镁聚合物。在无盐或含盐溶液中，绒泡菌辅肌动蛋白的分子量约为90000，在十二烷基硫酸盐溶液中为43000。硫酸铵盐析范围为50 - 65%饱和度，这与绒泡菌肌动蛋白（15 - 35%饱和度）不同。绒泡菌辅肌动蛋白不与绒泡菌肌球蛋白或肌肉重酶解肌球蛋白相互作用。当辅肌动蛋白与肌动蛋白的重量比增加时，形成的镁聚合物的流动双折射降低，在1:5的重量比时几乎变为零。在相同比例下，ATP酶活性达到最高水平（2.2×10⁻³ μmol ATP/（mg肌动蛋白·min））。向已加入2mM MgCl₂聚合的纯化绒泡菌F -肌动蛋白中加入绒泡菌辅肌动蛋白后，黏度迅速降低，这表明F -肌动蛋白丝断裂成较小片段或转化为镁聚合物。从海胆卵的丙酮粉中分离出一种性质与绒泡菌辅肌动蛋白相似的因子。
