Micronomicin/tobramycin binding with DNA: fluorescence studies using of ethidium bromide as a probe and molecular docking analysis

Two aminoglycosides, micronomicin(MN), and tobramycin(TB), binding with DNA were studied using various spectroscopic techniques including fluorescence, UV–Vis, FT-IR, and CD spectroscopycoupled with relative viscosityand molecular docking. Studies of fluorescence quenching and time-resolved fluorescence spectroscopyall revealed that MN/TB quenching the fluorescence of DNA–EB belonged to static quenching. The binding constantsand binding sites were obtained. The values of ΔH, ΔS, and ΔG suggested that van der Waals forceor hydrogen bond might be the main binding force. FT-IR and CD spectroscopyrevealed that the binding of MN/TB with DNA had an effect on the secondary structure of DNA. Binding mode of MN/TB with DNA was groove binding which was ascertained by viscosity measurements, CD spectroscopy, ionic strength, melting temperature (Tm), contrast experiments with single stranded (ssDNA), and double stranded DNA (dsDNA). Molecular docking analysis further confirmed that the groove binding was more...