期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2004
卷号：101
期号：33
页码：12159-12164
DOI：10.1073/pnas.0403545101
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：In a rotary motor FoF1-ATP synthase that couples H+ transport with ATP synthesis/hydrolysis, it is thought that an Foc subunit oligomer ring (c-ring) in the membrane rotates as protons pass through Fo and a 120{degrees} rotation produces one ATP at F1. Despite several structural studies, the copy number of Foc subunits in the c-ring has not been determined for any functional FoF1. Here, we have generated and isolated thermophilic Bacillus FoF1, each containing genetically fused 2-mer-14-mer c (c2-c14). Among them, FoF1 containing c2, c5, or c10 showed ATP-synthesis and other activities. When F1 was removed, Fo containing c10 worked as an H+ channel but Fos containing c9, c11 or c12 did not. Thus, the c-ring of functional FoF1 of this organism is a decamer. The inevitable consequence of this finding is noninteger ratios of rotation step sizes of F1/Fo (120{degrees}/36{degrees}) and of H+/ATP (10:3). This step-mismatch necessitates elastic twisting of the rotor shaft (and/or the side stalk) during rotation and permissive coupling between unit rotations by H+ transport at Fo and elementary events in catalysis at F1.
