Dodecamer rotor ring defines H+/ATP ratio for ATP synthesis of prokaryotic V-ATPase from Thermus thermophilus.
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 the increase in proton motive force (PMF) >110 mV, which is composed of a difference in proton concentration (DeltapH) and the electrical potential differences (DeltaPsi) 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 DeltapH, indicating DeltaPsi was not absolutely required for synthesis. Consistent with the H(+)/ATP ratio, cryoelectron micrograph images of 2D 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.
Toei
Masashi
M
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
Gerle
Christoph
C
Nakano
Masahiro
M
Tani
Kazutoshi
K
Gyobu
Nobuhiko
N
Tamakoshi
Masatada
M
Sone
Nobuhito
N
Yoshida
Masasuke
M
Fujiyoshi
Yoshinori
Y
Mitsuoka
Kaoru
K
Yokoyama
Ken
K
D000255:Adenosine Triphosphate / Q000096:biosynthesis*; D020134:Catalytic Domain; D020285:Cryoelectron Microscopy; D003460:Crystallization; D006859:Hydrogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D021122:Protein Subunits / Q000737:chemistry; D016963:Thermus thermophilus / Q000201:enzymology*; D025262:Vacuolar Proton-Translocating ATPases / Q000737:chemistry*
D021122:Protein Subunits; D006859:Hydrogen; D000255:Adenosine Triphosphate; D025262:Vacuolar Proton-Translocating ATPases