2,4-Diamino-6,7-dimethylpteridine as a fluorescent ligand for binding and sensing an orphan cytosine in RNA duplexes.

We report on a new fluorescent ligand, 2,4-diamino-6,7-dimethylpteridine, that can strongly and selectively bind to an orphan cytosine opposite an abasic site in RNA duplexes. We describe a significant effect of the substituents attached to the pteridine ring on the binding behavior in comparison with a structurally-similar pteridine derivative.