Background:
The processes of destruction and crosslinking of macromolecules occur simultaneously under the
influence of ultraviolet (UV) radiation in synthetic polymers, dry DNA and their concentrated solutions.
Objective:
The effect of UV radiation on calf thymus DNA in dilute solutions subjected to UV- irradiation was studied in
this work.
Method:
The calf thymus DNA was studied in dilute solutions using viscometry, absorption spectroscopy and
electrophoresis.
Results:
It was shown, that at a low concentration of DNA in the buffer solution ([DNA] = 85 μg / ml) under the influence
of UV radiation, the processes of destruction of macromolecules and an increase in their flexibility predominate, which is
accompanied by a gradual decrease in the viscosity of their solution. In addition, due to the low concentration of the
solution, intramolecular crosslinking of macromolecules predominates, which also reduces their size and, consequently,
the viscosity of the solution.
Conclusion:
It was concluded, that in dilute DNA solutions, due to the predominance of the processes of intramolecular
crosslinking of macromolecules over intermolecular, only constant processes of decreasing the sizes of DNA
macromolecules occur. As a result, its solubility remains virtually unchanged during UV irradiation. The described
comments are also excellently confirmed by the results of absorption spectroscopy and electrophoresis
Misincorporation of nucleotides by calf thymus DNA primase and elongation of primers containing multiple noncognate nucleotides by DNA polymerase alpha.