Specific and nonspecific metal ion-nucleotide interactions at aqueous/solid interfaces functionalized with adenine, thymine, guanine, and cytosine oligomers

Joseph G. Holland, Jessica N. Malin, David S. Jordan, Franz M. Geiger

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

This article reports nonlinear optical measurements that quantify, for the first time directly and without labels, how many Mg2+ cations are bound to DNA 21-mers covalently linked to fused silica/water interfaces maintained at pH 7 and 10 mM NaCl, and what the thermodynamics are of these interactions. The overall interaction of Mg2+ with adenine, thymine, guanine, and cytosine is found to involve -10.0 ± 0.3, -11.2 ± 0.3, -14.0 ± 0.4, and -14.9 ± 0.4 kJ/mol, and nonspecific interactions with the phosphate and sugar backbone are found to contribute -21.0 ± 0.6 kJ/mol for each Mg2+ ion bound. The specific and nonspecific contributions to the interaction energy of Mg2+ with oligonucleotide single strands is found to be additive, which suggests that within the uncertainty of these surface-specific experiments, the Mg 2+ ions are evenly distributed over the oligomers and not isolated to the most strongly binding nucleobase. The nucleobases adenine and thymine are found to bind only three Mg2+ ions per 21-mer oligonucleotide, while the bases cytosine and guanine are found to bind eleven Mg2+ ions per 21-mer oligonucleotide.

Original languageEnglish (US)
Pages (from-to)2567-2570
Number of pages4
JournalJournal of the American Chemical Society
Volume133
Issue number8
DOIs
StatePublished - Mar 2 2011

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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