Role of Active and Thermal Fluctuations in Biopolymer Dynamics

Life maintains itself as an out of equilibrium phenomenon and poses a fundamental difficulty in biological physics in establishing a predictive time-dependent statistical mechanical theoretical understanding. We develop a theoretical framework for predicting the combined influence of active and Brownian forces in biopolymer dynamics. The active forces exhibit a temporal correlation in their statistical behavior, capturing the processivity associated with the characteristic time scale of biological fluctuations such as enzymatic activity. Based on a path-integral formalism, we demonstrate that the non-equilibrium fluctuations can be mapped onto an “effective” time-dependent temperature that depends on active-force statistics. This theoretical picture suggests a hierarchy of length and timescale dependent behaviors, where local conformational fluctuations are unaffected by the presence of active forces, but large length-scale conformational dynamics are significantly altered. These results suggest that active fluctuations have a varying impact on biological events based on the time and length scale of information processivity. Furthermore, the concept of a time-dependent temperature provides a roadmap for the interpretation of in vivo measurements across wide observation timescales.