Speaker
Chun-Biu Li
(SU)
Description
Using single-molecule fluorescence approaches, the time
series of catalytic events of an enzymatic reaction can be
monitored, yielding a sequence of fluorescent “on”- and
“off”-states. An accurate on/off-assignment is complicated
by the intrinsic and extrinsic noise in every
single-molecule fluorescence experiment. Using simulated
data, the performance of the most widely employed binning
and thresholding approach was systematically compared to
change point analysis. It is shown that the underlying on-
and off-histograms as well as the off-autocorrelation are
not necessarily extracted from the “signal'' buried in
noise. The shapes of the on- and off-histograms are affected
by artifacts introduced by the analysis procedure and depend
on the signal-to-noise ratio and the overall fluorescence
intensity. When using change point analysis for data of the
enzyme α-chymotrypsin, no characteristics of dynamic
disorder was found. In light of these results, dynamic
disorder might not be a general sign of enzymatic reactions.
