Kanazawa H, Hama H, Rosen B P, Futai M
Arch Biochem Biophys. 1985 Sep;241(2):364-70. doi: 10.1016/0003-9861(85)90558-2.
A mutant gene for the gamma subunit of H+-translocating ATPase was cloned from Escherichia coli mutant NR70 isolated by B. P. Rosen [J. Bacteriol. 116, 1124-1129 (1973)]. Determination of its nucleotide sequence revealed a deletion of 21 base pairs between nucleotide residues 64 and 84, resulting in a deletion of seven amino acid residues (LysAlaMetGluMetValAla) from the amino-terminal portion. This deletion resulted in the loss of a hydrophobic domain of the subunit estimated by an analysis of its hydropathic character. Since F1 subunits are reported not to be assembled on the normal F0 portion of NR70, it is concluded that the hydrophobic domain deleted in the mutant subunit is important for assembly of the F1 portion. Introduction of a plasmid pNR70 carrying the mutant allele of NR70 into a wild-type strain gave no recombinants resistant to neomycin. This result suggested that the neomycin-resistant phenotype is not directly related to the defect in the gamma subunit of NR70.
从由B.P.罗森分离得到的大肠杆菌突变体NR70中克隆出了H⁺转运ATP酶γ亚基的一个突变基因[《细菌学杂志》116, 1124 - 1129(1973)]。对其核苷酸序列的测定显示，在核苷酸残基64和84之间缺失了21个碱基对，导致从氨基末端部分缺失了七个氨基酸残基（赖氨酸 - 丙氨酸 - 甲硫氨酸 - 谷氨酸 - 甲硫氨酸 - 缬氨酸 - 丙氨酸）。通过对其亲水性特征的分析估计，这种缺失导致了该亚基一个疏水域的丧失。由于据报道F1亚基不会组装在NR70的正常F0部分上，所以得出结论，突变亚基中缺失的疏水域对于F1部分的组装很重要。将携带NR70突变等位基因的质粒pNR70导入野生型菌株中，未得到对新霉素有抗性的重组体。这一结果表明，新霉素抗性表型与NR70的γ亚基缺陷没有直接关系。
