Kaneko M, Yamaguchi A, Sawai T
FEBS Lett. 1985 Dec 2;193(2):194-8. doi: 10.1016/0014-5793(85)80149-6.
Tritiated tetracycline was actively accumulated in inverted membrane vesicles prepared from Escherichia coli W3104rif, which has a transposon, Tn10, on the plasmid, R388, by means of a protonmotive force when NADH was added as an energy source. The tetracycline accumulation was reduced to about one-half the full value on the addition of a cation/proton-exchange ionophore, nigericin. In contrast, remarkable stimulation of the tetracycline accumulation was observed with a K+-specific ionophore, valinomycin. The accumulation of [3H]tetracycline could also be driven by an artificially imposed interior-acidic pH gradient (delta pH), but not, however, by an artificially imposed interior-positive membrane potential (delta psi). These results strongly indicate that the plasmid-encoded tetracycline transport was mainly due to an electrically neutral proton/tetracycline antiport system.
当添加烟酰胺腺嘌呤二核苷酸（NADH）作为能源时，氚标记的四环素通过质子动力被主动积累到从大肠杆菌W3104rif制备的反向膜泡中，该大肠杆菌在质粒R388上有一个转座子Tn10。添加阳离子/质子交换离子载体尼日利亚菌素后，四环素的积累量降至最大值的约二分之一。相反，使用钾离子特异性离子载体缬氨霉素时，观察到四环素积累有显著刺激。[3H]四环素的积累也可以由人为施加的内部酸性pH梯度（ΔpH）驱动，但不能由人为施加的内部正膜电位（Δψ）驱动。这些结果有力地表明，质粒编码的四环素转运主要归因于电中性的质子/四环素反向转运系统。
