Substrate Stiffness tunes the dynamics of polyvalent rolling motors

Nature has evolved many mechanisms for achieving directed motion on the subcellular level. The burnt-bridges ratchet (BBR) is one mechanism used to achieve superdiffusive molecular motion over long distances through the successive cleavage of surface-bound energy-rich substrate sites. The BBR mechanism is utilized throughout Nature: it can be found in bacteria, plants, humans, as well as non-life forms such as influenza. Recently, experimentalists have succeeded in creating synthetic versions of spherical BBRs. Experimental progress on both the synthetic and biological fronts has led to contradictory explanations as to the mechanistic origin for the observed velocities and directional persistence found for spherical BBR systems. In this talk I will discuss our recent findings that substrate stiffness influences the motor-like properties (eg. speed, processivity, superdiffusivity, and the dynamical mode) of BBRs. Our work has implications for the mechanism by which the influenza virus navigates pericellular space to infect cells, as well as provides a distinct example of an active matter system where directed motion arises from collective effects of substrate cleavage by individual coupled model enzymes.