Hong J S, Kaback H R
Proc Natl Acad Sci U S A. 1972 Nov;69(11):3336-40. doi: 10.1073/pnas.69.11.3336.
Two classes of mutants isolated from E. coli and Salmonella typhimurium are altered in respiration-coupled active transport, as studied in whole cells and/or isolated membrane vesicles. Mutant cells defective in D-lactate dehydrogenase (dld) transport amino acids and lactose normally. Membrane vesicles prepared from these mutants do not exhibit D-lactate-dependent transport, D-lactate oxidation, or D-lactate: dichlorophenolindophenol reductase activity. However, succinate-dependent transport is markedly enhanced in these mutants, without a corresponding increase in succinic dehydrogenase activity. The second class of mutants is defective in the coupling of electron transfer to active transport. Whole cells and membrane vesicles prepared from these etc mutants exhibit markedly reduced ability to transport amino acids, despite the ability of the vesicles to oxidize D-lactate, succinate, and NADH. Vectorial phosphorylation of alpha-methylglucoside by these mutants is normal. Electrontransfer coupling mutants are similar phenotypically to mutants uncoupled for oxidative phosphorylation (uncA), but have normal ATPase activity. Moreover, uncA mutants catalyze active transport as well as does the wild type. These experiments indicate that the ETC component is essential for the coupling of respiratory energy to active transport, and provide further evidence that the generation or utilization of ATP is not involved in these transport mechanisms.
从大肠杆菌和鼠伤寒沙门氏菌中分离出的两类突变体，在全细胞和/或分离的膜泡中进行研究时，其呼吸偶联主动运输发生了改变。缺乏D - 乳酸脱氢酶（dld）的突变体细胞运输氨基酸和乳糖的功能正常。由这些突变体制备的膜泡不表现出D - 乳酸依赖性运输、D - 乳酸氧化或D - 乳酸：二氯酚靛酚还原酶活性。然而，这些突变体中琥珀酸依赖性运输显著增强，而琥珀酸脱氢酶活性没有相应增加。第二类突变体在电子传递与主动运输的偶联方面存在缺陷。从这些etc突变体制备的全细胞和膜泡运输氨基酸的能力明显降低，尽管这些膜泡能够氧化D - 乳酸、琥珀酸和NADH。这些突变体对α - 甲基葡萄糖苷的向量磷酸化是正常的。电子传递偶联突变体在表型上与氧化磷酸化解偶联的突变体（uncA）相似，但具有正常的ATP酶活性。此外，uncA突变体催化主动运输的能力与野生型一样。这些实验表明，电子传递链组分对于呼吸能量与主动运输的偶联至关重要，并进一步证明ATP的产生或利用不参与这些运输机制。
