Design of Novel Bases on Recognition of GC Base Pairs of DNA by OligonucleotideDirected Triple Helix Formation

摘要

The binding of pyrimidine oligonucleotides containing cytosine at single sites ondouble helical DNA by triple helix formation is sensitive to pH. An important factor is the required protonation of the cytosine N-3 in the third strand to enable the formation of two Hoogsteen hydrogen bonds (G+GC triplet). Because oligonucleotide specificity could provide a method for artificial repression of viral and pathogenic diseases, it is desirable to design and synthesize a novel base that could bind GC base pairs strongly and selectively over a wide range of intracellular pH. The novel base, N-1-15-O-(bis(4-methoxyphenyl)phenylmethyl-2-