Effects of metal ions on thermal stabilities of DNA duplexes containing homo- and heterochiral mismatched base pairs: comparison of internal and terminal substitutions.

The effects of metal ions on the stabilities of duplexes containing a -homochiral and heterochiral mismatched base pairs were studied. In some duplexes containing an internal mismatched base pair, significant stabilization by Hg and Ag ions was observed. While, in duplexes containing a terminal mismatched base pair, only the duplexes containing T-T and T-T mispairs were significantly stabilized by Hg ions, and the stabilities of the duplexes containing T-T and T-T mispairs exceeded those of the corresponding homochiral matched duplex.