Interaction of sodium and potassium ions with sandwiched cytosine-, guanine-, thymine-, and uracil-base tetrads

✍ Scribed by Michael Meyer; Alexandre Hocquet; Jürgen Sühnel

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 569 KB
• Volume: 26
• Category: Article
• ISSN: 0192-8651
• DOI: 10.1002/jcc.20176

✦ Synopsis

Abstract

Nucleic acid tetraplexes and lipophilic self‐assembling G‐quadruplexes contain stacked base tetrads with intercalated metal ions as basic building blocks. Thus far, quantum‐chemical studies have been used to explore the geometric and energetic properties of base tetrads with and without metal ions. Recently, for the first time, work on a sandwiched G‐tetrad complex has been studied. We report here results of a systematic B3LYP density functional study on sandwiched G‐, C‐, U‐, and T‐tetrads with Na^+^ and K^+^ at different symmetries that substantially extend the recent work. The results include detailed information on total energies as well as on metal ion tetrad and base–base interaction energies. The geometrical parameters of the sandwiched metal ion complexes are compared to both experimental structures and to calculated geometries of complexes of single tetrads with metal ions. A microsolvation model explains the ion selectivity preference of K^+^ over Na^+^ in a qualitative sense. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 352–364, 2005