Journal
JOURNAL OF BIOLOGICAL CHEMISTRY
Volume 287, Issue 12, Pages 9633-9639Publisher
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M111.335356
Keywords
-
Categories
Funding
- Japan Society for the Promotion of Science
- Japan Science and Technology Agency
- Grants-in-Aid for Scientific Research [11J03653, 21000011] Funding Source: KAKEN
Ask authors/readers for more resources
ATP synthase is the key player of Mitchell's chemiosmotic theory, converting the energy of transmembrane proton flow into the high energy bond between ADP and phosphate. The proton motive force that drives this reaction consists of two components, the pH difference (Delta pH) across the membrane and transmembrane electrical potential (Delta psi). The two are considered thermodynamically equivalent, but kinetic equivalence in the actual ATP synthesis is not warranted, and previous experimental results vary. Here, we show that with the thermophilic Bacillus PS3 ATP synthase that lacks an inhibitory domain of the epsilon subunit, Delta pH imposed by acid-base transition and Delta psi produced by valinomycin-mediated K+ diffusion potential contribute equally to the rate of ATP synthesis within the experimental range examined (Delta pH -0.3 to 2.2, Delta psi -30 to 140 mV, pH around the catalytic domain 8.0). Either Delta pH or Delta psi alone can drive synthesis, even when the other slightly opposes. Delta psi was estimated from the Nernst equation, which appeared valid down to 1 mM K+ inside the proteoliposomes, due to careful removal of K+ from the lipid.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available