A generalized Davydov soliton model for energy transfer in alpha helical proteins

We propose a generalized Davydov model with higher order molecular interactions and excitations of dipole and quadrupole types with appropriate nonlinear coupling with phonons and study the underlying nonlinear molecular coherent excitations under continuum approximation in terms of solitons to represent energy transfer along the hydrogen bonding spines of the alpha helical proteins. We have identified six specific models at different orders of continuum approximation for particular choice of parameters under this new generalized model that support energy transfer in the form of solitons. In the general case, we have constructed the perturbed soliton and the perturbation analysis shows that the velocity and amplitude of the soliton do not change. (C) 2001 Elsevier Science B.V. All rights reserved.