Substeps in F1 Rotation

Solid horizontal lines are drawn 120° apart, and dotted lines are 30° below.


Slow playback at 1/1067 the original speed (recorded at 8,000 frames per second)


At speeds below the maximal, we were able to resolve substeps with an amplitude of ~90 ° and ~30° in the 120° step powered by the hydrolysis of one ATP molecule (see figure at left).  If you have very good eyes, you may be able to detect some of the substeps in the actual images on the right.  The 90° substep turned out to be driven by binding of ATP to a catalytic site on F1, and the 30° substep by the release of a hydrolysis product(s).  The hydrolysis reaction per se appeared to be mechanically almost silent.
                                                            Yasuda, R. et al., Nature 410, 898-904 (2001).