Spectral Study of the Binding of TMetAlPyP3 and ZnTMetAlPyP3 Porphyrins to DNA

In this work, according to the data obtained from the induced circular dichroism spectra, the studied porphyrin binds to DNA by the intercalation method, and its Zn-containing analog by the externally ordered interaction was revealed. The absorption spectra of the studied complexes were obtained at different DNA concentrations, and the binding parameters (K_b, n) of porphyrins with DNA were computed from the data at two values of the ionic strength of the solution. It is shown that the places for binding porphyrins become less accessible at a higher ionic strength of the solution. An increase in the melting temperature of DNA in the presence of a metal-containing porphyrin is also observed, as well as a decrease in the stabilizing effect of porphyrins for an increase in the ionic strength of the solution.