Importance of chiral recognition in designing metal-free ligands for G-quadruplex DNA

Four pairs of amino acid-functionalized naphthalenediimide enantiomers (d- and l-lysine derived NDIs) were screened toward G-quadruplex forming sequences in telomeres (h-TELO) and oncogene promoters: c-KIT1, c-KIT2, k-RAS and BCL-2. This is the first study to address the effect of point chirality toward G-quadruplex DNA stabilization using purely small organic molecules. Enantioselective behavior toward the majority of ligands was observed, particularly in the case of parallel conformations of c-KIT2 and k-RAS. Additionally, Nε-Boc-l-Lys-NDI and Nε-Boc-d-Lys-NDI discriminate between quadruplexes with parallel and hybrid topologies, which has not previously been observed with enantiomeric ligands.