PMID:22128167
| Citation |
Usukura, E, Suzuki, T, Furuike, S, Soga, N, Saita, E, Hisabori, T, Kinosita, K Jr and Yoshida, M (2012) Torque generation and utilization in motor enzyme F0F1-ATP synthase: half-torque F1 with short-sized pushrod helix and reduced ATP Synthesis by half-torque F0F1. J. Biol. Chem. 287:1884-91 |
|---|---|
| Abstract |
ATP synthase (F(0)F(1)) is made of two motors, a proton-driven motor (F(0)) and an ATP-driven motor (F(1)), connected by a common rotary shaft, and catalyzes proton flow-driven ATP synthesis and ATP-driven proton pumping. In F(1), the central γ subunit rotates inside the α(3)β(3) ring. Here we report structural features of F(1) responsible for torque generation and the catalytic ability of the low-torque F(0)F(1). (i) Deletion of one or two turns in the α-helix in the C-terminal domain of catalytic β subunit at the rotor/stator contact region generates mutant F(1)s, termed F(1)(1/2)s, that rotate with about half of the normal torque. This helix would support the helix-loop-helix structure acting as a solid "pushrod" to push the rotor γ subunit, but the short helix in F(1)(1/2)s would fail to accomplish this task. (ii) Three different half-torque F(0)F(1)(1/2)s were purified and reconstituted into proteoliposomes. They carry out ATP-driven proton pumping and build up the same small transmembrane ΔpH, indicating that the final ΔpH is directly related to the amount of torque. (iii) The half-torque F(0)F(1)(1/2)s can catalyze ATP synthesis, although slowly. The rate of synthesis varies widely among the three F(0)F(1)(1/2)s, which suggests that the rate reflects subtle conformational variations of individual mutants. |
| Links |
PubMed PMC3265869 Online version:10.1074/jbc.M111.305938 |
| Keywords |
Adenosine Triphosphate/biosynthesis; Catalysis; Catalytic Domain; Escherichia coli/enzymology; Escherichia coli/genetics; Escherichia coli Proteins/chemistry; Escherichia coli Proteins/genetics; Escherichia coli Proteins/metabolism; Helix-Loop-Helix Motifs; Mutation; Protein Structure, Tertiary; Proton-Motive Force/physiology; Proton-Translocating ATPases/chemistry; Proton-Translocating ATPases/genetics; Proton-Translocating ATPases/metabolism |
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