Jezek P, Bauer M, Trommer W E
Department of Membrane Transport Biophysics, Academy of Sciences of the Czech Republic Videnská 1083, Prague.
FEBS Lett. 1995 Mar 20;361(2-3):303-7. doi: 10.1016/0014-5793(95)00201-j.
Competition of fatty acids (FA) and alkylsulfonates with 5-DOXYL-stearic acid (5-SASL) binding to isolated mitochondrial uncoupling protein (UcP) is demonstrated using EPR spectroscopy. A distinct peak of the bound 5-SASL (h+1I) decreased with increasing concentration of competitors. Since alkylsulfonates are UcP substrates, it suggests that the FA binding site is located in the anion channel. Moreover, with increasing ATP the h+1I peak decreased and was smoothed with the 'micellar' peak into a single wider peak. A pH of 8.5 reversed this effect. It could reflect an allosteric release of 5-SASL from the ATP binding site which mimics the ATP gating mechanism.
利用电子顺磁共振波谱法证明了脂肪酸（FA）和烷基磺酸盐与5-脱氧硬脂酸（5-SASL）结合到分离的线粒体解偶联蛋白（UcP）上存在竞争关系。随着竞争剂浓度的增加，结合态5-SASL（h+1I）的一个明显峰降低。由于烷基磺酸盐是UcP的底物，这表明脂肪酸结合位点位于阴离子通道中。此外，随着ATP浓度增加，h+1I峰降低，并与“胶束”峰平滑成一个更宽的单峰。pH为8.5可逆转这种效应。这可能反映了5-SASL从ATP结合位点的变构释放，这模拟了ATP门控机制。
