Mechanism of Flagellar Motor Rotation in Bacteria

Abstract

It has been found recently that the bacterial flagellar motor is driven by a proton flux according to its electrochemical potential gradient across the membrane. A model is presented for the mechanism of rotation of this motor, in which loose coupling is assumed between the proton flux and the motor rotation. A directional torque to rotate the motor is produced as a result of the interaction in many pairs of two kinds of molecules arranged on two rings, which is regulated by the binding of protons. The torque is calculated as a function of the electrochemical potential gradient of proton and pH values inside and outside the cell. The results of calculation are compared with experimental data and some experimental methods for further examination of the model are proposed.