  We investigate the dynamics of an active gel of bundled microtubules that is
driven by clusters of kinesin molecular motors. Upon the addition of ATP, the
coordinated action of thousands of molecular motors drives the gel to a highly
dynamical turbulent-like state that persists for hours and is only limited by
the stability of constituent proteins and the availability of the chemical
fuel. We characterize how enhanced transport and emergent macroscopic flows of
active gels depend on relevant molecular parameters, including ATP, kinesin
motor, and depletant concentrations, microtubule volume fraction, as well as
the stoichiometry of the constituent motor clusters. Our results show that the
dynamical and structural properties of microtubule based active gels are highly
tunable. They also indicate existence of an optimal concentration of molecular
motors that maximize far-from-equilibrium activity of active isotropic MT gels.
