About the cover

February 2006 Volume 2 No 2

Real-time observation of enzymatic turnovers at the single-molecule level. English et al. (p 87) continuously moni-tored fluorescent spikes of individual products from enzymatic reactions of a single immobilized &β; -galactosidase molecule. They observed large fluctua-tions of the enzymatic activity across a range of timescales that they attributed to a rugged energy landscape, in which a single enzyme molecule interconverts among conformers with different enzy-matic activities. This result was recon-ciled with, and provided new insights into, the classic Michaelis-Menten equation of enzyme kinetics (see also News &&; Views by Walter, p 66). Cover art by Erin Boyle, based on images of Badlands National Park, South Dakota (USA) provided by Brian English.