RT Journal Article
SR Electronic
T1 Inferring quantity and qualities of superimposed reaction rates in single molecule survival time distributions
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 679258
DO 10.1101/679258
A1 Matthias Reisser
A1 Johannes Hettich
A1 Timo Kuhn
A1 J. Christof M. Gebhardt
YR 2019
UL http://biorxiv.org/content/early/2019/06/21/679258.abstract
AB Actions of molecular species, for example binding of transcription factors to chromatin, are intrinsically stochastic and may comprise several mutually exclusive pathways. Inverse Laplace transformation in principle resolves the rate constants and frequencies of superimposed reaction processes, however current approaches are challenged by single molecule fluorescence time series prone to photobleaching. Here, we present a genuine rate identification method (GRID) that infers the quantity, rates and frequencies of dissociation processes from single molecule fluorescence survival time distributions using a dense grid of possible decay rates. In particular, GRID is able to resolve broad clusters of rate constants not accessible to common models of one to three exponential decay rates. We validate GRID by simulations and apply it to the problem of in-vivo TF-DNA dissociation, which recently gained interest due to novel single molecule imaging technologies. We consider dissociation of the transcription factor CDX2 from chromatin. GRID resolves distinct, decay rates and identifies residence time classes overlooked by other methods. We confirm that such sparsely distributed decay rates are compatible with common models of TF sliding on DNA.