Math Biology Seminar Abstracts

Wednesday August 28, 2002

Energy transduction of F1 ATPase and related issues

Hongyun Wang

Department of Mathematics, University of California at Santa Cruz

Abstract: In this talk I will start by reviewing briefly our modeling study of the F1 ATP synthase. Then I will focus on two issues. The first issue is about how the force is directly generated in the ATP hydrolysis cycle. An ATP in solution diffuses to the catalytic site and becomes weakly bound. Then it proceeds from weak binding to tight binding as the bonds form progressively (the binding transition). A nearly constant force is generated efficiently during the binding transition. The role of hydrolysis is to help release products so that the cycle can repeat. We call this the binding zipper model. The second issue is about the Stokes efficienc of a protein motor working against a viscous drag. For macroscopic motors, because of the large inertia, a viscous drag has approximately the same effect as a conservative force. This is not true for protein motors. I will show that for protein motors the Stokes efficiency is different from the thermodynamic efficiency. A high thermodynamic efficiency implies that the motor motion and chemical reaction are tightly coupled while a high Stokes efficiency implies that the motor force is nearly constant. Thus, measuring both efficiencies can help deduce the motor mechanism.

For more information contact J. Keener, 1-6089