Preparation and metal ion-binding of 4-N-substituted cytosine pairs in DNA duplexes.

Abstract

We report the synthesis and metal ion-binding properties of DNA duplexes containing 4-N-substituted cytosine base pairs. Thermal denaturation studies of these modified DNA duplexes in the presence of various metal ions revealed that the DNA duplexes containing 4-N-carboxymethylcytosine (1) base pair(s) bound Ag (I), Ni(II), and Cu(II) ions. Moreover, ESI-TOF MS analysis of the DNA duplexes containing 1-1 base pair(s) in the presence of Cu(II) ions was consistent with one 1-1 base pair region binding one equivalent of Cu(II) ions. These results indicate that the DNA duplexes containing 1-1 base pair(s) may be useful as a new metal ion-binding motif.