Enhancement of the Binding Ability of a Ligand for Nucleobase Recognition by Introducing a Methyl Group

Abstract

The recognition ability of pteridine derivatives for nucleobases opposite an abasic (AP) site in an oligodeoxynucleotide (ODN) duplex is enhanced by using a propylene residue (Spacer-C3) as an AP site. The recognition ability is further enhanced both by attaching methyl groups to a fluorescent ligand and by measuring the fluorescence response at 5°C; 6.2 × 10⁶ M^-1 of the binding constant is attained between 2-amino-6,7-dimethyl-4-hydroxypteridine and guanine opposite the AP site in water.