Regulation of lactose permease activity by the phosphoenolpyruvate:sugar phosphotransferase system: evidence for direct binding of the glucose-specific enzyme III to the lactose permease.
Regulation of lactose permease activity by the phosphoenolpyruvate:sugar phosphotransferase system: evidence for direct binding of the glucose-specific enzyme III to the lactose permease.
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磷酸烯醇丙酮酸：糖磷酸转移酶系统对乳糖通透酶活性的调节：葡萄糖特异性酶 III 与乳糖通透酶直接结合的证据。
DOI：
10.1073/pnas.79.5.1457
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发表时间：
1982
影响因子：
11.1
通讯作者：
SaierJr,MH
中科院分区：
文献类型：
--
作者：
Osumi,T;SaierJr,MH
葡萄糖特异性酶III（酶IIIglc）的磷酸烯醇丙酮酸：糖磷酸转移酶系统和乳糖通透酶之间的相互作用进行了研究，从大肠杆菌菌株，过度生产的乳糖通透酶的膜片段。底物的通透酶显着和特异性刺激结合酶IIIglc的膜。糖刺激的酶IIIglc的结合被推断为特异于乳糖通透酶，因为它（i）依赖于通透酶的量，（ii）仅由通透酶的糖底物促进，以及（iii）在不存在（但不存在）硫代-β-D-二半乳糖苷的情况下通过用N-乙基马来酰亚胺处理膜而完全消除。结合的pH依赖性与硫代-β-D-二半乳糖苷与通透酶结合的报道相似。磷酸烯醇式丙酮酸阻止酶IIIglc的结合的乳糖通透酶的存在下（但不是不存在）的磷酸转移酶系统的其他磷酸转移组分。这些结果支持的假设，酶IIIglc，在其去磷酸化的形式，调节乳糖通透酶的活性，通过直接的蛋白质-蛋白质相互作用。
Interaction between the glucose-specific enzyme III (enzyme IIIglc) of the phosphoenolpyruvate:sugar phosphotransferase system and the lactose permease was studied with membrane fragments from an Escherichia coli strain that overproduces the lactose permease. Substrates of the permease markedly and specifically stimulated binding of enzyme IIIglc to the membranes. The sugar-stimulated binding of enzyme IIIglc was concluded to the specific to the lactose permease because it (i) was dependent on the amount of the permease, (ii) was promoted only by sugar substrates of the permease, and (iii) was completely eliminated by treatment of the membranes with N-ethylmaleimide in the absence (but not the presence) of thio-beta-D-digalactoside. The pH dependence of binding was similar to that reported for the binding of thio-beta-D-digalactoside to the permease. Phosphoenolpyruvate prevented the binding of enzyme IIIglc to the lactose permease in the presence (but not the absence) of the other phosphate transfer components of the phosphotransferase system. These results support the hypothesis that enzyme IIIglc, in its dephosphorylated form, modulates the activity of the lactose permease by a direct protein-protein interaction.