A comparative study of DNA complexation with Mg(II) and Ca(II) in aqueous solution: major and minor grooves bindings.

摘要: Although structural differences for the Mg-DNA and Ca-DNA complexes are provided in solid state, such comparative study aqueous solution has been less investigated. The aim of this was to examine bindings Mg Ca cations with calf thymus DNA at physiological pH, using constant concentration (1.25 or 12.5 mM) various concentrations metal ions (2 μM–650 μM). Capillary electrophoresis, UV-visible, Fourier transform infrared spectroscopic methods were used determine cation-binding modes, binding constants, variations solution. Direct Ca-PO2 evident by major spectral changes (shifting splitting) backbone PO2 asymmetric stretching 1222 cm−1 K = 4.80 × 105 M−1, whereas an indirect Mg-phosphate interaction occurred (due lack shifting splitting phosphate band cm−1) 5.6 104 M−1. metal-base directly 3.20 M−1 indirectly cation 3.0 Both minor groove observed no alteration B-DNA conformation.