The influence of ionic strength on the binding of a water soluble porphyrin to nucleic acids.

AUTOR(ES)

Pasternack, R F

RESUMO

The ionic strength dependences of the binding of tetrakis (4-N-methylpyridyl)porphine (H2TMpyP) to poly(dG-dC) and calf thymus DNA have been determined. For the former system the results are typical of other intercalators, i.e., a plot of log K vs log [Na+] is linear albeit with a slope which suggests that the "effective charge" of the porphyrin is closer to two than the formal charge of +4. For calf thymus DNA, the binding profile is not completely compatible with the predictions of condensation theory. Whereas the avidity of binding does decrease with increasing [Na+] as predicted, of greater interest is the relocation of the porphyrin from GC-rich regions to AT-rich regions as the ionic strength increases.

Documentos Relacionados

• Cooperative binding of m-AMSA to nucleic acids.
• Thermodynamic extent of counterion release upon binding oligolysines to single-stranded nucleic acids.
• The binding of an avian myeloblastosis virus basic 12,000 dalton protein to nucleic acids.
• Thermodynamics of the interactions of m-AMSA and o-AMSA with nucleic acids: influence of ionic strength and DNA base composition.
• Influence of ionic strength on the viscosities and water loss of bentonite suspensions containing polymers