Local dynamics in biological macromolecules

The diffusive approach in the optimized Rouse-Zimm approximation to segment relaxation in the nanosecond time domain (ORZLD) is extended to consider chains of nonequivalent units as occurring in biological macromolecules. The correlation times for second-order time correlation functions of each virtual bond on the chain are calculated for some homopolypeptides, and random and regular copolypeptides. The expected correlation times for biological macromolecules organized in multiple domains are discussed via a simple model of the ORZLD hierarchy. Dynamic bond correlation times are compared with static local persistence lengths.