Kumari, BeenaBeenaKumariYadav, AkankshaAkankshaYadavPany, Sushree P.Sushree P.PanyPradeepkumar, P. I.P. I.PradeepkumarKanvah, SriramSriramKanvah2025-08-302025-08-302019-01-0110.1016/j.jphotobiol.2018.10.0072-s2.0-85057897062http://repository.iitgn.ac.in/handle/IITG2025/2268130529810Guanine (G) quadruplexes (G4) are nucleic acid secondary structures formed by G-rich sequences, commonly found in human telomeric and oncogene-promoter regions, have emerged as targets for regulation of multiple biological processes. Considering their importance, targeting the G-quadruplex structure with small molecular binders is extremely pertinent. In this work, red emitting water soluble fluorophores bearing push-pull substituents were synthesized and examined for their interaction with human telomeric G4 and duplex (ds) -DNAs. The presence of a strong electron donating (dimethylamino) and electron withdrawing (cationic pyridinium) groups linked through a conjugated double bond helps in water solubility and enabling the emission in the near IR region (>700–nm). Binding of this cationic dye to the G4-DNA yields multiple-fold emission enhancement (~70 fold with G4-DNA vs. ~7 fold with ds-DNA) along with hypsochromic wavelength shifts (35 nm with G4-DNA and 8 nm with ds-DNA). The remarkable emission changes, ~2–4 fold enhanced binding efficiency noted with the antiparallel conformation of G4-DNA indicates preferential selectivity over ds-DNA. The molecular docking and dynamics studies of the ligands with duplex and G4-DNA were performed, and they provide insights into the mode of binding of these dyes with G4-DNA and supplement the experimental observations.falseG4-quadruplexes | NIR fluorescence | Solvatochromism | Styrylpyridinium dyesArticle18732682128-136January 201921arJournal21WOS:000456228700016