Molecular-level implementation of fixed-output-torque models for FliG conformation dynamics

Develop a molecular-level mechanism that implements models treating the motor output torque under a given load as a fixed parameter modulating the conformation dynamics of all FliG subunits in the C-ring, specifying how a global output torque causally influences the switching kinetics of individual FliG subunits.

Background

Some prior approaches modeled torque-dependent FliG dynamics by assuming the motor’s output torque, at a given load, acts as a fixed, global parameter that modulates all FliG subunits’ conformational switching. While such phenomenological models can reproduce certain behaviors, their molecular basis has not been specified.

The paper argues that a physically consistent treatment must include torque balances on both the rotor and stators and proposes that local, stator-engaged torques affect individual FliG subunits (Global Mechanical Coupling). Nonetheless, the question of how earlier fixed-output-torque phenomenology can be grounded at the molecular level remains explicitly open.