Water soluble extended naphthalene diimides as pH fluorescent sensors and G-quadruplex ligands

Full text: Unavailable

Publisher: Royal Society of Chemistry

Preprint: archiving allowed. Upload

Postprint: archiving restricted: Upload

  • 12 months embargo

Published version: archiving forbidden. Upload

Policy details (opens in a new window). Data provided by SHERPA/RoMEO

Contact authors Contact

Abstract
Extended naphthalene diimides (NDIs) fused to 1,4-dihydropyrazine-2,3-dione, containing two solubilizing moieties, have been synthesized. Fluorescence spectra of the new NDIs were remarkably affected by pH, as the second deprotonation of the dihydropyrazinedione moiety (pK(a) 6.9) switched off the emission. Binding to a G-quadruplex folded oligonucleotide and stoichiometry were evaluated by FRET melting assay and CD analysis. G-quadruplex binding was strongly enhanced shifting from pH 7.4 to pH 6.0 as a consequence of the dihydropyrazinedione moiety protonation. Cytotoxicity studies using two human telomerase-positive cell lines (HT29 and A549) revealed that the best G-quadruplex ligand was very active against the colon cell line, with an EC(50) of 300 nM.