Breather-mediated energy transfer in proteins

In this paper we investigate how energy is redistributed across protein structures, following localized kicks, within the framework of a non-linear network model. We show that energy is directed most of the times to a few specific sites, systematically within the stiffest regions. This effect is sharpened as the energy of the kicks is increased, with fractions of transferred energy as high as 70 % already for kicks above 20 kcal/mol. Remarkably, we show that such site-selective, high-yield transfers mark the spontaneous forma-tion of spatially localized, time-periodic vibrations at the target sites, acting as efficient energy-collecting centers. A comparison of our simulations with a previously developed theory reveals that such energy-pinning modes are dis-crete breathers, able to carry energy across the structure in an quasi-coherent fashion by jumping from site to site.