two motors
F1 motor
Fo motor
FRET approach
work in progress

ATP-induced rotation of the g-subunit within the a3b3 barrel has been convincingly visualized by a single enzyme approach.

In these experiments, the a3b3g-fragment of the F1 portion from Bacillus PS3 was attached via three His-tags onto the glass surface of a coverslip, and, as an indicator, a fluorescent mm-long actin filament was connected to the g-subunit. The orientation of the actin filament with respect to the a3b3 hexamer was monitored by videomicroscopy. At very low ATP concentrations, rotation occurred in discrete 120 steps consistent with sequential ATP hydrolysis at the three b-subunits.

F1 motor
overview    ATP