Okret S, Wikström A C, Gustafsson J A
Biochemistry. 1985 Nov 5;24(23):6581-6. doi: 10.1021/bi00344a041.
The composition of the molybdate-stabilized glucocorticoid receptor (GR) complex has been investigated with a monoclonal antibody against the steroid-binding Mr 94 000 (94K) GR protein. It was concluded that one antibody molecule binds one 94K GR molecule. This finding constituted the basis for calculating the number of antibodies bound to the molybdate-stabilized nonactivated GR complex, which has an Mr of 302 000 (302K). Gel filtration on Sephacryl S-400 and density gradient centrifugation showed that only one antibody molecule bound to the molybdate-stabilized GR complex (calculated relative molecular mass for the antibody--molybdate-stabilized GR complex, 456 000; relative molecular mass for one antibody molecule, 157 000). Furthermore, experiments performed with a second antibody immunoprecipitation assay in the presence of an excess of both antibody and GR confirmed the above results. The possibility of steric hindrance not allowing more than one antibody molecule to bind to the molybdate-stabilized GR complex could be excluded. These results suggest that the molybdate-stabilized GR complex with an Mr of 302K only contains one steroid-binding 94K GR molecule and therefore represents a heteromeric complex.
已使用针对类固醇结合型94000 Mr（94K）糖皮质激素受体（GR）蛋白的单克隆抗体研究了钼酸盐稳定的糖皮质激素受体（GR）复合物的组成。得出的结论是，一个抗体分子结合一个94K GR分子。这一发现为计算与钼酸盐稳定的非活化GR复合物结合的抗体数量奠定了基础，该复合物的Mr为302000（302K）。在Sephacryl S - 400上进行凝胶过滤和密度梯度离心表明，只有一个抗体分子与钼酸盐稳定的GR复合物结合（抗体 - 钼酸盐稳定的GR复合物的计算相对分子质量为456000；一个抗体分子的相对分子质量为157000）。此外，在抗体和GR均过量存在的情况下，用第二种抗体免疫沉淀试验进行的实验证实了上述结果。可以排除空间位阻导致不止一个抗体分子无法与钼酸盐稳定的GR复合物结合的可能性。这些结果表明，Mr为302K的钼酸盐稳定的GR复合物仅包含一个类固醇结合型94K GR分子，因此代表一种异聚复合物。
