Discrete Davydov's soliton in α-helical protein molecule with anharmonic hydrogen bond and thermal noise

An improvement of the Davydov's model for energy transfer in α-helix protein is proposed. Using hyperbolic cosine potential type to model hydrogen bond potential, we have obtained from the adiabatic approximation, a discrete nonlinear Schrödinger equation with inverse hyperbolic sine nonlinearity. Using the two-dimensional discrete map approach, we have found a linearly stable intrinsic localized mode of the corresponding developed equation. Mobility of the intrinsic localized mode was achieved by moving the local impurity hypothesized as the anomalous band energy. The reactivity of the discrete breather under thermal noise was studied numerically with the Langevin's approach. It was shown that the intrinsic localized mode in the developed model keep its shape longer under thermal bath.