Seeing a Molecular Motor at Work

The molecular machinery of life can be visualized by crystal structure analysis, which provides still pictures at atomic resolution (∼0.1 nm), as well as by pulsed-laser methods that can yield recordings of events ranging from vibronic relaxation (10−14 s) to catalysis (10−6 to 10−3 s). The ultimate goal has been to merge high-resolution space and time recordings and advance from still pictures to movies of molecules at work. High-speed scanning probe microscopy provides excellent spatial resolution and has been extended into the time domain of chemical activity (1, 2). On page 755 of this issue, Uchihashi et al. (3) use this technique to examine the FOF1-ATPase, the rotary enzyme that synthesizes adeno sine triphosphate (ATP), the universal fuel of cells. The study demonstrates the power of atomic force microscopy (AFM) in observing the cellular machinery at nanometer and millisecond resolution.