Stochastic kinetics of molecular motors: mathematical models of kinesin and ribosome

Debashish Chowdhury
Department of Physics, Indian Institute of Technology Kanpur

(September 20, 2011 10:30 AM - 11:30 AM)

Stochastic kinetics of molecular motors: mathematical models of kinesin and ribosome

Abstract

Molecular motors are either proteins or macromolecular complexes which move along filamentous tracks utilizing some form of input energy. In contrast to their macroscopic counterparts, these natural nano-machines are (i) made of soft matter, (ii) driven by isothermal engines, (iii) far from thermodynamic equilibrium, and (iv) their dynamics is dominated by viscous forces and thermal noise. Mathematical models based on master equation (or, Langevin equation) are the most appropriate for a quantitative theory of their stochastic kinetics. In this talk I'll begin with a brief discussion on the basic theoretical and experimental techniques that are used for studying molecular motors. One characteristic feature of their "directed", albeit noisy, movements is an alternating sequence of pause and translocation. The main aim of this talk is to show how important "hidden" information on the kinetics of such motors can be extracted from the statistics of the durations of pause+translocation. I'll present our recent results on dwell-time distributions of two motors, namely, a member of the kinesin superfamily and the ribosome. I'll also mention the nature of collective spatio-temporal organization of the motors on the track and the effects of their crowding on the dwell time distribution.