Monticello R A, Brusilow W S
Department of Biochemistry, Wayne State University School of Medicine, Detroit, Michigan 48201.
J Bacteriol. 1994 Mar;176(5):1383-9. doi: 10.1128/jb.176.5.1383-1389.1994.
We studied the effect of the delta subunit of the Escherichia coli F1 ATPase on the proton permeability of the F0 proton channel synthesized and assembled in vivo. Membranes isolated from an unc deletion strain carrying a plasmid containing the genes for the F0 subunits and the delta subunit were significantly more permeable to protons than membranes isolated from the same strain carrying a plasmid containing the genes for the F0 subunits alone. This increased proton permeability could be blocked by treatment with either dicyclohexyl-carbodiimide or purified F1, both of which block proton conduction through the F0. After reconstitution with purified F1 in vitro, both membrane preparations could couple proton pumping to ATP hydrolysis. These results demonstrate that an interaction between the delta subunit and the F0 during synthesis and assembly produces a significant change in the proton permeability of the F0 proton channel.
我们研究了大肠杆菌F1 ATP酶的δ亚基对体内合成和组装的F0质子通道质子通透性的影响。从携带含有F0亚基和δ亚基基因的质粒的unc缺失菌株中分离出的膜，其质子通透性明显高于从携带仅含有F0亚基基因的质粒的同一菌株中分离出的膜。这种增加的质子通透性可以通过用二环己基碳二亚胺或纯化的F1处理来阻断，这两种物质都能阻断质子通过F0的传导。在体外与纯化的F1重构后，两种膜制剂都能将质子泵浦与ATP水解偶联起来。这些结果表明，在合成和组装过程中，δ亚基与F0之间的相互作用会使F0质子通道的质子通透性发生显著变化。
