Regulatory interplay between proton motive force, ADP, phosphate, and subunit epsilon in bacterial ATP synthase.

TitleRegulatory interplay between proton motive force, ADP, phosphate, and subunit epsilon in bacterial ATP synthase.
Publication TypeJournal Article
Year of Publication2007
AuthorsFeniouk, BA, Suzuki, T, Yoshida, M
JournalJ Biol Chem
Volume282
Issue1
Pagination764-72
Date Published2007 Jan 05
ISSN0021-9258
KeywordsAdenosine Diphosphate, Adenosine Triphosphatases, Adenosine Triphosphate, Escherichia coli, Hydrogen-Ion Concentration, Hydrolysis, Liposomes, Mitochondrial Proton-Translocating ATPases, Models, Biological, Models, Molecular, Molecular Conformation, Phosphates, Protein Structure, Tertiary, Proteolipids, Protons
Abstract

ATP synthase couples transmembrane proton transport, driven by the proton motive force (pmf), to the synthesis of ATP from ADP and inorganic phosphate (P(i)). In certain bacteria, the reaction is reversed and the enzyme generates pmf, working as a proton-pumping ATPase. The ATPase activity of bacterial enzymes is prone to inhibition by both ADP and the C-terminal domain of subunit epsilon. We studied the effects of ADP, P(i), pmf, and the C-terminal domain of subunit epsilon on the ATPase activity of thermophilic Bacillus PS3 and Escherichia coli ATP synthases. We found that pmf relieved ADP inhibition during steady-state ATP hydrolysis, but only in the presence of P(i). The C-terminal domain of subunit epsilon in the Bacillus PS3 enzyme enhanced ADP inhibition by counteracting the effects of pmf. It appears that these features allow the enzyme to promptly respond to changes in the ATP:ADP ratio and in pmf levels in order to avoid potentially wasteful ATP hydrolysis in vivo.

DOI10.1074/jbc.M606321200
Alternate JournalJ. Biol. Chem.
Citation Key10.1074/jbc.M606321200
PubMed ID17092944