The ATP synthase: the understood, the uncertain and the unknown.

TitleThe ATP synthase: the understood, the uncertain and the unknown.
Publication TypeJournal Article
Year of Publication2013
AuthorsWalker, JE
JournalBiochem Soc Trans
Date Published2013 Feb 01
KeywordsATP Synthetase Complexes, Hydrolysis, Models, Molecular, Protein Conformation, Uncertainty

The ATP synthases are multiprotein complexes found in the energy-transducing membranes of bacteria, chloroplasts and mitochondria. They employ a transmembrane protonmotive force, Δp, as a source of energy to drive a mechanical rotary mechanism that leads to the chemical synthesis of ATP from ADP and Pi. Their overall architecture, organization and mechanistic principles are mostly well established, but other features are less well understood. For example, ATP synthases from bacteria, mitochondria and chloroplasts differ in the mechanisms of regulation of their activity, and the molecular bases of these different mechanisms and their physiological roles are only just beginning to emerge. Another crucial feature lacking a molecular description is how rotation driven by Δp is generated, and how rotation transmits energy into the catalytic sites of the enzyme to produce the stepping action during rotation. One surprising and incompletely explained deduction based on the symmetries of c-rings in the rotor of the enzyme is that the amount of energy required by the ATP synthase to make an ATP molecule does not have a universal value. ATP synthases from multicellular organisms require the least energy, whereas the energy required to make an ATP molecule in unicellular organisms and chloroplasts is higher, and a range of values has been calculated. Finally, evidence is growing for other roles of ATP synthases in the inner membranes of mitochondria. Here the enzymes form supermolecular complexes, possibly with specific lipids, and these complexes probably contribute to, or even determine, the formation of the cristae.

Alternate JournalBiochem. Soc. Trans.
Citation Key10.1042/BST20110773
PubMed ID23356252
Grant ListMC_U105663150 / / Medical Research Council / United Kingdom