Mimmack M L, Gallagher M P, Pearce S R, Hyde S C, Booth I R, Higgins C F
Department of Biochemistry, University of Dundee, Scotland, United Kingdom.
Proc Natl Acad Sci U S A. 1989 Nov;86(21):8257-61. doi: 10.1073/pnas.86.21.8257.
Periplasmic binding protein-dependent transport systems mediate the accumulation of many diverse substrates in prokaryotic cells. Similar transport systems, including the P-glycoprotein responsible for multidrug resistance in human tumors, are also found in eukaryotes. The mechanism by which energy is coupled to the accumulation of substrate by these transport systems has been controversial. In this paper we demonstrate that ATP hydrolysis occurs in vivo concomitantly with transport. These data strongly suggest that ATP hydrolysis directly energizes substrate accumulation by these transport systems. The apparent stoichiometry is one to two molecules of ATP hydrolyzed per molecule of substrate transported.
周质结合蛋白依赖性转运系统介导原核细胞中多种不同底物的积累。在真核生物中也发现了类似的转运系统,包括负责人类肿瘤多药耐药性的P-糖蛋白。这些转运系统将能量与底物积累偶联的机制一直存在争议。在本文中,我们证明ATP水解在体内与转运同时发生。这些数据有力地表明,ATP水解直接为这些转运系统的底物积累提供能量。明显的化学计量比是每转运一分子底物水解一到两分子ATP。