Single molecule techniques offer a unique tool studying the dynamical behaviour of individual molecules, and provide the possibility to construct distributions from individual events rather than from a signal stemming from an ensemble of molecules. Observing the activity of individual lipase molecules for extended periods of time (hours), we get long trajectories, made of "on-state" and "off-state" events. The waiting time probability density function (PDF) of the off-state and the state-correlaiton function fit stretched exponentials, independent of the substrate concentration in a certain range. The data analysis unravels correlations between off-state events. These findings imply that the fluctuating enzyme model, which involves a spectrum of enzymatic conformations that interconvert on the timescale of the catalytic activity, best describes the observed enzymatic activity.
This contribution summarizes some of our recent published results.
Conference Committee Involvement (1)
Noise and Fluctuation in Biological, Biophysical, and Biomedical Systems