EMBO Rep. 2006 March; 7(3): 276–282.
doi: 10.1038/sj.embor.7400646.
PMCID: PMC1456893
Copyright © 2006, European Molecular Biology Organization
Review Article
Review
Catalytic and mechanical cycles in F-ATP synthases: Fourth in the Cycles Review Series
Peter Dimroth,1a Christoph von Ballmoos,1 and T Meier1
1Institute of Microbiology, ETH Zürich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich-Hönggerberg, Switzerland
aTel: +41 44 632 3321; Fax: +41 44 632 1378; E-mail: dimroth@micro.biol.ethz.ch
Received November 22, 2005; Accepted January 19, 2006.
Cycles have a profound role in cellular life at all levels of organization. Well-known cycles in cell metabolism include the tricarboxylic acid and the urea cycle, in which a specific carrier substrate undergoes a sequence of chemical transformations and is regenerated at the end. Other examples include the interconversions of cofactors, such as NADH or ATP, which are present in the cell in limiting amounts and have to be recycled effectively for metabolism to continue. Every living cell performs a rapid turnover of ATP to ADP to fulfil various energetic demands and effectively regenerates the ATP from ADP in an energy-consuming process. The turnover of the ATP cycle is impressive; a human uses about its body weight in ATP per day. Enzymes perform catalytic reaction cycles in which they undergo several chemical and physical transformations before they are converted back to their original states. The ubiquitous F1Fo ATP synthase is of particular interest not only because of its biological importance, but also owing to its unique rotational mechanism. Here, we give an overview of the membrane-embedded Fo sector, particularly with respect to the recent crystal structure of the c ring from Ilyobacter tartaricus, and summarize current hypotheses for the mechanism by which rotation of the c ring is generated.
Keywords: ATP cycle, catalytic reaction cycle, F-ATP synthase, ion translocation model, mechanical rotation, c ring structure, Na+ binding site
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