Hirata H, Ohno K, Sone N, Kagawa Y, Hamamoto T
J Biol Chem. 1986 Jul 25;261(21):9839-43.
The proton-translocating ATPase of the thermophilic bacterium PS3 was incorporated into a planar phospholipid bilayer, and its electrogenicity was directly demonstrated. The enzyme (TF0F1) consists of a catalytic portion, F1, and a membrane-integrated portion, Fo. A short-circuit current of up to 1 nA/cm2 was generated upon the addition of ATP, and the direction of the current indicated the flow of positive charges from the TF1 side to the TF0 side. The generation of the electric current was progressively suppressed by the presence of an inhibitor of TF1 such as NaN3 or adenyl-5'-yl imidodiphosphate. An open-circuit membrane potential of 40-120 mV was also demonstrated (more negative on the TF1 side), which was inhibited by NaN3. Furthermore, an applied voltage of -180 mV (TF1 side negative) was sufficient to prevent the generation of electric current dependent on ATP hydrolysis, which indicated that the electrogenicity of TF0F1 is some 180 mV under the conditions studied. From these results it was tentatively concluded that the number of protons transported across the bilayer/mol of ATP is more than 3.
嗜热细菌PS3的质子转运ATP酶被整合到平面磷脂双分子层中，并直接证明了其产电特性。该酶（TF0F1）由催化部分F1和膜整合部分Fo组成。加入ATP后会产生高达1 nA/cm2的短路电流，电流方向表明正电荷从TF1侧向TF0侧流动。TF1的抑制剂如NaN3或腺苷-5'-亚氨二磷酸的存在会逐渐抑制电流的产生。还证明了存在40 - 120 mV的开路膜电位（TF1侧更负），该电位被NaN3抑制。此外，施加-180 mV的电压（TF1侧为负）足以阻止依赖ATP水解的电流产生，这表明在所研究的条件下TF0F1的产电能力约为180 mV。从这些结果初步得出结论，每摩尔ATP跨双分子层转运的质子数超过3个。
