Synthesis and crystallographic analysis of short pyridine-based oligoamides as DNA-targeting supramolecular binders

In this study, the synthesis of the pyridine peptides 1-4, formed from amino-picolinic acid, and pyridine peptide 5, made from coupling of a mono-protected pyridine diamine to a mono-protected pyridine dicarboxylic acid and the X-ray crystallographic structures of 1 and 5 are discussed, along with their supramolecular interactions in the solid state. The structure of these compounds showed that they possess concave appearance which can be employed to bind to nucleic acids through multiple hydrogen bonding, which would facilitate the formation of helical-based pyridine oligoamides as novel DNA-binding molecules. This was proven by carrying out DNA denaturation studies and ethidium displacement assay on 5, but, by using MTT assays, 5 was shown to be cytotoxic against drug-resistant chronic myeloid leukaemia K562 cell-line.