Kabanov V A, Evdakov V P, Mustafaev M I, Antipina A D
Mol Biol (Mosk). 1977 May-Jun;11(3):582-97.
Interaction of bovine serum albumin (BSA) with quaternized poly-4-vinyl pyridine (PE) in aqueous solutions at pH 7 was studied. It was shown that in a wide range of the ratios of the components (nBSA/nPE) soluble stable cooperative complexes were formed. At the same time a certain critical content of the protein exists at which the system loses its homogeneity. Complex formation is not accompanied by protein denaturation. At smaller nBSA/nPE ratios non-homogeneous distribution of protein globulas among polyelectrolite macromolecules was found; this corresponded to the "all or none" principle. Using ultracentrifugation technique viscosimetric measurements and electron microscopy it was shown that the soluble complexes exist in the form of rode-like particles consisting of protein globules stabilized by polycation chains. Such particle can be considered as a model of nucleoprotein complex. At certain crytical nBSA/nPE rations the rod-like particles aggregate with additional number of BSA-molecules and form more complicate soluble and insoluble cooperative complexes. Possible structural models of the complexes described were suggested and the thermodinamic and kinetic cryteria of their self-assembly were discussed.
研究了牛血清白蛋白（BSA）与季铵化聚4-乙烯基吡啶（PE）在pH 7水溶液中的相互作用。结果表明，在广泛的组分比例（nBSA/nPE）范围内形成了可溶的稳定协同复合物。同时存在一定的蛋白质临界含量，超过此含量体系会失去均一性。复合物的形成不伴随蛋白质变性。在较小的nBSA/nPE比例下，发现蛋白质球状体在聚电解质大分子间呈非均相分布；这符合“全或无”原则。通过超速离心技术、粘度测量和电子显微镜观察表明，可溶复合物以棒状颗粒形式存在，该颗粒由被聚阳离子链稳定的蛋白质球状体组成。这种颗粒可被视为核蛋白复合物的模型。在特定的临界nBSA/nPE比例下，棒状颗粒会与额外数量的BSA分子聚集，形成更复杂的可溶和不溶协同复合物。文中提出了所描述复合物可能的结构模型，并讨论了其自组装的热力学和动力学标准。
