Universal features of first-passage time statistics and kinetics in the few-encounter limit

Date

Nov 29, 2016

Time

11:00 AM - 12:00 PM

Speaker

Aljaz Godec

Affiliation

University of Potsdam)

Language

en

Main Topic

Physik

Other Topics

Physik

Description

The first-passage time (FPT) problem, denoting the time it takes for a diffusing particle to reach its target for the first time, is central to the kinetics of molecular reactions in chemistry and molecular biology. In the talk we will explain the behavior of smooth FPT densities, for which all moments are finite, such those observed when a particle searches for its target in a finite volume -- a scenario typical for cellular regulation. We will demonstrate universal long-time FPT asymptotics for a broad variety of transport processes. However, gene regulation kinetics, as uncovered by modern experimental techniques in single cells, often occur in the so-called few-encounters limit, where few binding events determine the regulatory outcome. In this regime we will show that a time-scale separation between direct and reflected indirect FPT trajectories gives rise to a universal proximity effect: Direct paths, heading more or less straight from the point of release to the target, become typical and focused, with a narrow spread of the corresponding first-passage times. The proximity effect is independent of details of the transport, highlighting the robust character of our results, which readily explain both the speed and the precision enhancement for the regulation of colocalized genes.

Last modified: Nov 28, 2016, 8:59:25 AM