Chestukhina G G, Kostina L I, Zalunin I A, Kotova T S, Katruka S P, Kuznetsov Iu S, Stepanov V M
Biokhimiia. 1977 Sep;42(9):1660-7.
Pure crystals (at least 99% purification) of sigma-endotoxin were isolated from Bac. thuringiensis var. galleriae. The complete dissolution of crystals might be achieved by the increase of pH up to 12 and higher or by a combined action of S = S-reducing and denaturing agents. Electrophoresis of the solubilized crystal proteins in 5% polyacrylamide gels containing 0,1% sodium dodecyl sulfate and 8 M urea reveals two major bands corresponding to molecular weights of 120000--140000 (65%) and 65000 (8-10%), and some minor components whose molecular weights varied from 65000 to 340000. Urea (3--8 M) causes to partial dissolution of the crystals; the component with molecular weight of 65000 is mainly found in the solution (component A). In dithioerythritol extracts at pH 9 the major component of the crystal is the protein with molecular weight 120000--140000 (component B). The crystals, alkali-soluble components and proteins isolated from crystals by selective extraction (3--8 M urea or 0.01 M dithioerythrytol, pH 9) were found toxic for the larvae of Galleria mellonella.
从苏云金芽孢杆菌蜡螟变种中分离出了纯度至少为99%的纯晶体σ-内毒素。通过将pH值提高到12及更高，或通过硫醇还原和变性剂的联合作用，可实现晶体的完全溶解。在含有0.1%十二烷基硫酸钠和8M尿素的5%聚丙烯酰胺凝胶中对溶解的晶体蛋白进行电泳，结果显示出两条主要条带，分别对应分子量为120000 - 140000（65%）和65000（8 - 10%），还有一些分子量在65000至340000之间变化的次要成分。3 - 8M的尿素会导致晶体部分溶解；分子量为65000的成分主要存在于溶液中（成分A）。在pH值为9的二硫赤藓糖醇提取物中，晶体的主要成分是分子量为120000 - 140000的蛋白质（成分B）。通过选择性提取（3 - 8M尿素或0.01M二硫赤藓糖醇，pH值为9）从晶体中分离出的晶体、碱溶性成分和蛋白质，对蜡螟幼虫有毒性。
