Engineering Approaches to Biomolecular Motors

Engineering Approaches to Biomolecular Motors: From in vitro to in vivo Wednesday Speaker Abstracts

The Nonequilibrium Statistical Thermodynamics of Biomolecular Motors

Jason A. Wagoner

, Ken Dill,

Stony Brook University, Stony Brook, NY, USA.

Biomolecular motors operate through a complex sequence of transitions that transduce the

chemical energy of nucleotide hydrolysis into work against some mechanical or chemical

gradient. We use statistical physics to study motor operation. We integrate structural and

dynamical information of molecular motors into this theory to understand the origins of

fluctuations, dissipation, entropy production, etc. for these systems operating arbitrarily far from

equilibrium. These analyses give insight into both biological mechanism and evolutionary design

principles of molecular motors.

This presentation will discuss the difference between enthalpic driving forces (like the breaking

of a high energy bond) and entropic driving forces (like a concentration gradient) for molecular

motors. We show that motors can take large mechanical steps driven by enthalpic driving forces

to operate not only faster but also more efficiently than a motor taking small steps. This gives an

interesting perspective on the high-energy phosphate bond of ATP, the central driving force of

nonequilibrium processes in the cell. We also discuss other characteristics of motor operation

that are specific and fundamental to understanding small nonequilibrium systems: the role of

fluctuations around mean behavior, the organization of conformational transitions, and the

location and height of kinetic barriers. These characteristics have important consequences on

performance metrics (power output, efficiency, etc.) of molecular motors.