Research Project
Grant-in-Aid for Scientific Research (B)
ATP synthesis by V-ATPase from the thermophilic bacterium Thermus thermophilus driven by the acid-base transition was investigated. The rate of ATP synthesis increased in parallel with increase in proton motive force (PMF) above 110 mV, which is composed of a difference in proton concentration (ΔpH) and the electrical potential differences (ΔΨ) across membranes. The optimum rate of synthesis reached 85 s^<-1> and the H^+/ATP ratio of 4.0± 0.1 was obtained. ATP was synthesized at a considerable rate solely by ΔpH indicating ΔΨ was not absolutely required for synthesis. Consistent with the H^+/ATP ratio, cryo-electron micrograph images of two-dimensional crystals of the membrane-bound rotor ring of the V-ATPase at 7.0 A resolution showed the presence of 12 V_o-c subunits each composed of two transmembrane helices. These results indicate that symmetry mismatch between the rotor and catalytic domains is not obligatory for rotary ATPases/synthases.
All 2008 2007 2006
All Journal Article (11 results) (of which Peer Reviewed: 6 results) Presentation (2 results) Book (1 results)
The Journal of Biological Chemistry 283(In press)
Nature Structure and Molecular Biology 15(In press)
Nat Struct Mol Biol. 15
JBiol Chem (in press)
The Proceedings of the National Academy of Sciences of the United States of America 103
Pages: 20256-20261
Proc Nati Acad Sci USA. 103
The Journal of Biological Chemistry 281
Pages: 38582-38592
Journal of Structural Biology 153
Pages: 200-206
JBiol Chem 281
J. Structural Biology 153