[Interaction of DNA with calcium ions by a vibrational spectroscopy]

Mol Biol (Mosk). May-Jun 1995;29(3):574-84.
[Article in Russian]

Abstract

DNA complexes with Ca2+ ions formed in films at various relative humidities were studied by IR-spectroscopy for molar concentration ratio of calcium ions and DNA phosphate groups [Ca2+]/[P] = 0.4-20. It is shown that the transition of DNA complexed with Ca2+ ions into B-form occurs at higher average numbers (n) of water molecules absorbed per nucleotide: n > 18 at the ratio [Ca2+]/[P] = 10, n > 24 at [Ca2+]/[P] = 20 and n > 12 in the absence of Ca2+ ions. This shows stronger binding of water molecules in the hydrate shell of DNA-Ca2+ if compared with free DNA. The results confirm a model proposed earlier. Ca2+ ions interact with phosphate oxygens of DNA and with N(7) nitrogens of guanine forming chelated complexes.

Publication types

  • English Abstract

MeSH terms

  • Animals
  • Calcium / chemistry*
  • Cations
  • Cattle
  • DNA / chemistry*
  • Oxygen / chemistry
  • Spectrophotometry, Infrared / methods
  • Water / chemistry

Substances

  • Cations
  • Water
  • DNA
  • Oxygen
  • Calcium