1: Cell  1998 Jun 26;93(7):1117-24 

F1-ATPase is a highly efficient molecular motor that rotates with discrete 120
degree steps.

Yasuda R, Noji H, Kinosita K Jr, Yoshida M.

Department of Physics, Faculty of Science and Technology, Keio University,
Yokohama, Japan.

A single molecule of F1-ATPase, a portion of ATP synthase, is by itself a rotary
motor in which a central gamma subunit rotates against a surrounding cylinder
made of alpha3beta3 subunits. Driven by three catalytic betas, each fueled with
ATP, gamma makes discrete 120 degree steps, occasionally stepping backward. The
work done in each step is constant over a broad range of imposed load and is
close to the free energy of hydrolysis of one ATP molecule.

PMID: 9657145 [PubMed - indexed for MEDLINE]