Mobility of discrete multibreathers in the exciton dynamics of the Davydov model with saturable nonlinearities.
We show that the state of amide-I excitations in proteins is modeled by the discrete nonlinear Schrödinger equation with saturable nonlinearities. This is done by extending the Davydov model to take into account the competition between local compression and local dilatation of the lattice, thus leading to the interplay between self-focusing and defocusing saturable nonlinearities. Site-centered (sc) mode and/or bond-centered mode like discrete multihump soliton (DMHS) solutions are found numerically and their stability is analyzed. As a result, we obtained the existence and stability diagrams for all observed types of sc DMHS solutions. We also note that the stability of sc DMHS solutions depends not only on the value of the interpeak separation but also on the number of peaks, while their counterpart having at least one intersite soliton is instable. A study of mobility is achieved and it appears that, depending on the higher-order saturable nonlinearity, DMHS-like mechanism for vibrational energy transport along the protein chain is possible.
Laboratory of Mechanics, Department of Physics, Faculty of Science, University de Yaounde I, P.O. Box 812, Yaounde, Cameroon.
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Tchinang Tchameu
Laboratory of Mechanics, Department of Physics, Faculty of Science, University de Yaounde I, P.O. Box 812, Yaounde, Cameroon.
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Togueu Motcheyo
Laboratory of Mechanics, Department of Physics, Faculty of Science, University de Yaounde I, P.O. Box 812, Yaounde, Cameroon.
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Tchawoua
D000255:Adenosine Triphosphate / Q000737:chemistry; D000577:Amides / Q000737:chemistry*; D003198:Computer Simulation; D008962:Models, Theoretical; D009038:Motion; D017711:Nonlinear Dynamics; D011506:Proteins / Q000737:chemistry*; D011789:Quantum Theory
D000577:Amides; D011506:Proteins; D000255:Adenosine Triphosphate