It Takes Two to Make a Thing Go Right: Boosting Current in Coupled Motors

Catalysis-driven synthetic molecular motors operate in loose mechanochemical coupling regime, where stochastic backward steps persist even as fuel is continuously consumed. Here we ask a simple question: whether coupling multiple such motors can boost their averaged current. By simulating rotaxane-based motors with two classes of models – particle-based nonequilibrium molecular dynamics and jump-diffusion models – we show that coupling two motors mechanically can increase their average current. This current boost originates from accelerated activity induced by coupling, despite some loss of directional bias. The lost bias can be largely recovered by raising the fuel concentration, demonstrating a general design strategy: accelerate motion through coupling and restore bias through stronger driving. These results reveal that reciprocal mechanical interactions, though symmetric in nature, can be integrated into design principles to amplify the performance of catalysis-driven molecular machines.