Selective recognition of a C-G base-pair in the parallel DNA triple-helical binding motif.

Selective recognition of a C-G base-pair within the parallel DNA triple-helical binding motif was achieved by a third strand containing the base 5-methyl pyrimidin-2-one. The third strand affinities (K(D)) for a representative 15-mer duplex sequence containing all four Watson-Crick base pairs (X-Y) in the center are C-G (26 nM) >> A-T (270 nM) approximately T-A (350 nM) > G-C (ca 700 nM).