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标题：Sodium ion cycling mediates energy coupling between complex I and ATP synthase
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作者：Anja C. Gemperli ; Peter Dimroth ; Julia Steuber 等
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：2003
卷号：100
期号：3
页码：839-844
DOI：10.1073/pnas.0237328100
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We show here sodium ion cycling between complex I from Klebsiella pneumoniae and the F1F0 ATP synthase from Ilyobacter tartaricus in a reconstituted proteoliposome system. In the course of NADH oxidation by complex I, an electrochemical sodium ion gradient was established and served as a driving force for the synthesis of ATP from ADP and phosphate. In the opposite direction, the {Delta}[IMG]f1.gif" ALT="Formula" BORDER="0">Na+ generated by ATP hydrolysis could be coupled to NADH formation by reversed electron transfer from ubiquinol to NAD. For reverse electron transfer, a transmembrane voltage larger than 30 mV was obligatory. No NADH-driven proton transport into the lumen of proteoliposomes was detected. We conclude that Na+ is used as the exclusive coupling ion by the enterobacterial complex I.