Effect of divalent cations on antiparallel G-quartet structure of d(G4T4C4)

The thermodynamic parameters of an antiparallel G-quartet formation of d(G(4)T(4)G(4)) with 1 mM divalent cation (Mg2+, Ca2+, Mn2+, Co2+, and Zn2+) were obtained. The thermodynamic parameters showed that the divalent cation destabilizes the antiparallel G-quartet of d(G(4)T(4)G(4)) in the Following order: Zn2+ > Co2+ > Mn2+ > Mg2+ > Ca2+. In addition, a higher concentration of a divalent cation induced a transition from an antiparattel to a parallel G-quartet structure. These results indicate that these divalent cations are a good tool for regulating the G-quartet structures. (C) 2001 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.