Impact of electromagnetic field on charge transport processes in macromolecules

Brizhik Larissa

Bogolyubov Institute for Theoretical Physics, Kyiv, Ukraine

e-mail: brizhik@bitp.kiev.ua

Two types of the impact of electromagnetic field on charge transport processes in macromolecules are discussed within the soliton mechanism. The solitons are formed in alpha-helical proteins and represent bound states of electrons and the local deformation of the polypeptide chains, stabilized by hydrogen bonds [1]. They can carry energy and charge in the phosphorylation processes in biological systems on macroscopic distances almost without energy dissipation. One of the impacts of electromagnetic field on solitons is nonthermal resonant effect, which takes place at certain frequencies of the field, and which constitutes a nonlinear mechanism for the biological effects of low-intensity electromagnetic radiation (EMR). The second type of the impact is related with the change of the dynamics of solitons induced by the field, called “ratchet dynamics”. The latter is the appearance of the directed current in the system induced by a periodic nonbiased (i.e., with the zero meanvalue) force.

Study of the properties of self-trapped electrons in the presence of the external EMR shows, that such radiation affects solitons, and therefore, the redox process in general. First of all, the EMR of certain frequency can cause dissociation of solitons [2], i.e., break of the bound state and transition of an electron from a bound state into the electron band. Such almost free electrons propagating along macromolecules, emit phonons, and therefore, are decelerated. As the result, efficiency of the charge transport processes significantly decreases which affects metabolism of the biological organism. The corresponding resonant frequency of EMR is determined by the soliton binding energy and corresponds to the millimeter wavelength range.

External EMR affects also the dynamics of solitons [3-5]. First of all, their velocity and dynamic mass in the alternating field attain dependence on the frequency of the field. In particular, the velocity is an oscillating function of time with the frequency of the EMR. During the oscillatory motion solitons emit sound waves in the backward and forward directions. This dynamic resonant frequency of the field is connected with the resonant absorption of energy by a soliton from the field and generation of acoustic waves. This frequency is determined by the characteristic time scale of the retardation effects which, in its turn, is determined as the ratio of the soliton width to the sound velocity. The generated sound waves dissipate in the polypeptide chain which can result in the local heating of the system. On the other hand, such sound waves propagating along the macromolecule as in a channel can carry some additional information and/or change the conformational states of the molecule, excite some other local modes, vibrations of the side groups, etc. This can change qualitatively some functional processes connected with conformational states of macromolecules or their fragments, since EMR of the corresponding frequencies causes the oscillations of solitons including oscillations of the chain distortion.

Another dynamical aspect of the effect of the periodic in time unbiased field is the appearance of the drift of solitons along macromolecules. Such a drift takes place in spatially asymmetrical macromolecules provided the intensity of the filed and its period exceed some critical values. The corresponding estimate shows that this critical intensity of the field is comparable and even lower than the intensity of the field on the biomembranes.

Thus, the suggested mechanism shows that EMR has a specific influence on the amide-I solitons and electrosolitons. This can constitute one of the mechanisms of the impact of cosmic weather on living systems. It explains also experimentally observed nonthermal effects of microwave electromagnetic fields on biosystems. It proves the importance of further detailed study of bioeffects of EMR and possible bioeffects of electromagnetic pollution.

References

1.   A.S. Davydov. Solitons in Molecular Systems (Reidel, Dordrecht, 1985).

2.   A.A. Eremko, Dokl. Ac. Nauk UkrSSR, 3 (1984) 52-55.

3.   L. Brizhik, L. Cruzeiro-Hansson, A. Eremko. J. Biol. Physics 24, 19-39 (1998).

4.   L.S. Brizhik, A.A. Eremko. Electromagn. Biology and Medicine, 24, 243-255 (2005).

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