Stability and structures of the DNA base tetrads: A role of metal ions

Abstract

Nucleic acids can form complex structures that consist of multi-strands, which play a vital role in many biological processes. Quantum chemistry studies of the polyads of the nucleic acid bases (NABs) strongly suggest that all of them (NABs) can form stable tetrad structure in cyclic form through the H-bonding between the neighboring bases. All of the cyclic form tetrads possess the strong cooperativity of the hydrogen bonds. The cooperative effects should play a key role in the formation of stable tetraplexes. The existence of cation in the cavity of the tetrads greatly improves the stability of the tetraplexes. Metals can also replace the protons in the bases to form tetrads. This phenomenon could be extremely important in the construction of variety of newly designed nanomaterials. DNA bases are also able to form larger species. The studies of isoG quintet reveal that metal ions are crucial for regulating the strand association. © 2010 Springer Science+Business Media B.V.