Dalibor Chevizovich1, Vasilije Matic1*, and Zeljko Przulj1
1 ”Vinča” Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade P.O.Box 522, 11001 Belgrade, Serbia
cevizd [at] vin.bg.ac.rs
Abstract
Molecular chains (such as protein chains with alpha-helical secondary structure, DNA and RNA molecules) can play the role of “bridges” for the highly efficient transfer of various types of submolecular excitations (vibron excitations or electrons) over very long distances (comparable to the length of the molecular chain itself). In the case when this process takes place in living cells, the biomolecule is placed in an environment where it is usually in thermodynamic equilibrium with the “heat bath”. As a result, the structural elements of the molecular chain perform mechanical oscillations. In the general case, such mechanical oscillations disrupt the ability of the molecular bridge to transfer the excitation over a longer distance.
On the other side, by interacting with the thermal oscillations of the structure, excitations injected into the molecule may be trapped and can form a stable self-trapped (polaron-like) state. Such quasiparticles can move through the structure with minimal energy loss. In this way, the high efficiency of energy and charge transport in living cells can be explained. However, the properties of the possibly formed polaron quasiparticle must also be affected by the presence of the donor molecule.
Here, we have discussed the mechanism of excitation transfer from a molecular structure (donor molecule) to the molecular chain. The presence of the donor structure and the temperature influence on the energy of the self-trapped excitation were considered in the dependence of the basic energy parameters of the molecular bridge. The obtained results indicate the possibility of the formation of two types of self-trapped states: a quasi-free excitation, which can easily move through the molecular bridge, and a localized, practically immobile excitation, which is similar to a non-adiabatic polaron quasiparticle.
Keywords: energy transfer, information transfer, biomolecular structures, self-trapping, polaron quasiparticle
Acknowledgment: Supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia and by the Project within the Cooperation Agreement between the JINR, Dubna, Russian Federation and Ministry of Education and Science of the Republic of Serbia.
