[Analysis of exciton parameters in DNA. Exciton waves in DNA as one of the reasons of mutagenesis].
Formulae were obtained for the quantitative analysis of the following parameters of excitons in DNA: 1) the lifetime of electronic excitation; 2) the numbers of exciton runs along the DNA sequence; 3) the energy loss by an exciton for one run; 4) the maximum length of the DNA sequence capable of deactivating an exciton for one run. The maximum and minimum ranges for the constant of electronic excitation migration was determined to meet the requirement of inductive-resonance energy transfer for the case of strong interaction. The constant of exciton energy migration was shown to depend on the activation energy, which is equal to the energy of absorbed quantum. An analytical formula was derived to determine the number of quanta the DNA molecule is able to absorb, depending on its length, without nonlinear effects (without overlapping of spatial areas of electronic excitation). By this formula, DNA sequences consisting of only identical AT and GC nucleotide pairs and aggregate AT + GC (in the ratio 1:1) DNA sequences ranging from 1 up to 10(10) base pairs were analyzed. The results of the analysis suggest that the overlapping of spatial areas of electronic excitation induced by a single ultraviolet quantum occurs in short DNA sequences characteristic of prokaryotes. To achieve the same effects on long DNA sequences specific for eukaryotes, DNA must synchronously absorb a great number of ultraviolet quanta. Based on the above results, the following conclusions were made: 1) disturbances in the normal activity of DNA and RNA polymerases may be due to electromagnetic field, which is caused by the oscillatory relaxation of vibronic levels of nucleotides. The energy enters the vibronic levels of nucleotides from an exciton running along the DNA sequence; 2) the increase in the noncoding DNA sequences in eukaryotes due to evolution is a way of DNA protection from undesirable mutations; 3) prokaryotes must possess a greater potentiality and a higher rate of mutagenesis in comparison with eukaryotes, which is proved by their greater diversity in nature.
Vasil'kov
S L
SL
Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia. vasilkov_sergey@mail.ru
D000465:Algorithms; D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D004735:Energy Transfer; D008956:Models, Chemical; D016296:Mutagenesis; D011789:Quantum Theory; D014466:Ultraviolet Rays
D004247:DNA