Shliankevich M A, Polotskaia A B, Drize O B, Ivanova T A, Shapot V S
Biokhimiia. 1980 Jul;45(7):1215-21.
The interaction of SV40 T-antigen and viral DNA was studied by using adsorption of DNA-protein complexes on nitrocellulose filters. The T-antigen purification procedure included ion-exchange chromatography on DEAE-cellulose, selective adsorption of cellular proteins on single-stranded DNA-cellulose, chromatography on heparin-Sepharose and removal of cell proteins by an immunosorbent. Only the latter step allowed to remove the contamination of cellular DNA-binding proteins, judging from the reaction of T-antigen neutralization by specific antibodies. It was shown that T-antigen and cellular DNA-binding proteins interact with SV40 DNA at different values of pH, namely ah 6,0-6,4 and 7,9, respectively. The T-antigen obtained was passed through a column with native DNA-cellulose at pH and ionic strength values optimal for interaction with DNA. The bulk of T-antigen (30-40%) did not bind to native thymus DNA and did not interact with SV40 DNA. It is assumed that this fraction is a form of T-antigen, which undergoes structural or functional changes during specific interaction with viral or cellular DNAs.
利用DNA - 蛋白质复合物在硝酸纤维素滤膜上的吸附作用，对SV40 T抗原与病毒DNA的相互作用进行了研究。T抗原的纯化过程包括在DEAE - 纤维素上进行离子交换色谱、在单链DNA - 纤维素上选择性吸附细胞蛋白、在肝素 - 琼脂糖上进行色谱以及通过免疫吸附去除细胞蛋白。从特异性抗体对T抗原的中和反应判断，只有最后一步能够去除细胞DNA结合蛋白的污染。结果表明，T抗原和细胞DNA结合蛋白分别在不同的pH值下与SV40 DNA相互作用，即分别在pH 6.0 - 6.4和7.9时。将获得的T抗原在对与DNA相互作用最适宜的pH和离子强度值下通过含有天然DNA - 纤维素的柱子。大部分T抗原（30 - 40%）不与天然胸腺DNA结合，也不与SV40 DNA相互作用。据推测，这一部分是T抗原的一种形式，它在与病毒或细胞DNA的特异性相互作用过程中发生了结构或功能上的变化。
