Dupuis A, Issartel J P, Lunardi J, Satre M, Vignais P V
Biochemistry. 1985 Jan 29;24(3):728-33. doi: 10.1021/bi00324a029.
Upon treatment of beef heart mitochondrial oligomycin sensitivity conferring protein (OSCP) with [14C]-N-ethylmaleimide ( [14C]NEM) or dithiobis(nitro[14C] benzoate), 1 mol of either SH reagent was incorporated per mol of OSCP. Radiolabeling occurred at the level of the only cysteine residue, Cys-118, present in the OSCP sequence reported by Ovchinnikov et al. [Ovchinnikov, Y. A., Modyanov, N. N., Grinkevich, V. A., Aldanova, N. A., Trubetskaya, O. E., Nazimov, I. V., Hundal, T., & Ernster, L. (1984) FEBS Lett. 166, 19-22]; it did not alter the biological activity of OSCP tested in a reconstituted F0-F1 system that catalyzed oligomycin-sensitive ATPase activity or ATP-Pi exchange. The parameters of [14C]NEM-OSCP binding to isolated beef heart mitochondrial F1 were assessed by equilibrium dialysis. Addition of trace amounts of Tween 20 prevented unspecific adsorption of OSCP. The binding curves showed that each F1 possesses a high-affinity OSCP binding site (Kd = 0.08 microM) and two low-affinity OSCP binding sites (Kd = 6-8 microM). Binding of OSCP to the high-affinity site on F1 is probably responsible for the ability of OSCP to confer oligomycin sensitivity to F1 in the ATPase complex.
用[14C]-N-乙基马来酰亚胺（[14C]NEM）或二硫代双（硝基[14C]苯甲酸）处理牛心线粒体寡霉素敏感性赋予蛋白（OSCP）时，每摩尔OSCP掺入1摩尔的任何一种巯基试剂。放射性标记发生在Ovchinnikov等人报道的OSCP序列中唯一的半胱氨酸残基Cys-118处[Ovchinnikov, Y. A., Modyanov, N. N., Grinkevich, V. A., Aldanova, N. A., Trubetskaya, O. E., Nazimov, I. V., Hundal, T., & Ernster, L. (1984) FEBS Lett. 166, 19 - 22]；它并未改变在催化寡霉素敏感性ATP酶活性或ATP-Pi交换的重组F0-F1系统中测试的OSCP的生物学活性。通过平衡透析评估[14C]NEM-OSCP与分离的牛心线粒体F1结合的参数。添加痕量的吐温20可防止OSCP的非特异性吸附。结合曲线表明，每个F1具有一个高亲和力的OSCP结合位点（Kd = 0.08 microM）和两个低亲和力的OSCP结合位点（Kd = 6 - 8 microM）。OSCP与F1上高亲和力位点的结合可能是OSCP在ATP酶复合物中赋予F1寡霉素敏感性的原因。
