On the quantum dynamics of Davydov solitons in protein $\alpha$-helices

The transport of energy inside protein $\alpha$-helices is studied by deriving a system of quantum equations of motion from the Davydov Hamiltonian with the use of the Schr\"odinger equation and the generalized Ehrenfest theorem. Numerically solving the system of quantum equations of motion for different initial distributions of the amide I energy over the peptide groups confirmed the generation of both moving or stationary Davydov solitons. In this simulation the soliton generation, propagation, and stability were found to be dependent on the symmetry of the exciton-phonon interaction Hamiltonian and the initial site of application of the exciton energy.