title: Unravelling the Binding Mechanism of a Poly(cationic) Anthracenyl Fluorescent Probe with High Affinity toward Double-Stranded DNA.
abstract: We report the synthesis, spectroscopy, and the DNA binding properties of a biocompatible, water-soluble, polycationic two-photon absorbing anthracenyl derivative (Ant-PIm) specifically designed for biorelated applications. Detailed insights into the Ant-PIm-DNA binding interaction are provided by using several spectroscopic approaches, including UV-vis absorption, circular dichroism (CD), Fourier-transform infrared spectroscopy (FTIR), steady-state, and time-resolved fluorescence techniques. Absorption and fluorescence quantitative data analysis show a strong Ant-PIm-duplex interaction with binding constants of Kf= 4.7 ± 0.2 × 105M-1, 7.1 ± 0.3 × 105M-1, and 1.0 ± 0.1 × 106M-1at 298, 304, and 310 K, respectively. Spectral changes observed upon DNA binding provide evidence for a complex formation with off-on fluorescence pattern, which can be related to two consecutive binding equilibria. Results of DNA binders displacement and iodide quenching experimental assays unambiguously point to the groove binding mode of Ant-PIm to the DNA-helicate. Thermodynamic and chemical denaturation studies suggest that long-range interactions of hydrophobic nature regulate the association of Ant-PIm with the biopolymer. The ionic strength dependence of the binding constant shows that electrostatic component has an important contribution to the overall Gibbs free energy. FTIR and CD data provide evidence of partial modification of the B-DNA secondary structure, while the increase in the melting temperature clearly indicates the enhancement of the thermal stability of the duplex. Furthermore, the two-photon absorption cross section spectrum determined using the two-photon excited fluorescence (TPEF) technique shows a strong 2PA maximum at 820 nm with a σ2> 800 GM, which emphasizes the advantageous combination of biological and optical properties possessed by this positively charged bioprobe.
authors.affiliation: Advanced Materials Engineering and Modelling Group, Faculty of Chemistry, Wroclaw University of Science and Technology , Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.
authors.forename: Marco
authors.initials: M
authors.lastname: Deiana
authors.affiliation: Laboratoire de Chimie, CNRS UMR 5182, Ecole Normale Supérieure de Lyon, Université Lyon 1 , 69007 Lyon, France.
authors.forename: Bastien
authors.initials: B
authors.lastname: Mettra
authors.affiliation: Advanced Materials Engineering and Modelling Group, Faculty of Chemistry, Wroclaw University of Science and Technology , Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Matczyszyn
authors.affiliation: Laboratoire de Chimie, CNRS UMR 5182, Ecole Normale Supérieure de Lyon, Université Lyon 1 , 69007 Lyon, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Pitrat
authors.affiliation: Advanced Materials Engineering and Modelling Group, Faculty of Chemistry, Wroclaw University of Science and Technology , Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Olesiak-Banska
authors.affiliation: Laboratoire de Chimie, CNRS UMR 5182, Ecole Normale Supérieure de Lyon, Université Lyon 1 , 69007 Lyon, France.
authors.forename: Cyrille
authors.initials: C
authors.lastname: Monnereau
authors.affiliation: Laboratoire de Chimie, CNRS UMR 5182, Ecole Normale Supérieure de Lyon, Université Lyon 1 , 69007 Lyon, France.
authors.forename: Chantal
authors.initials: C
authors.lastname: Andraud
authors.affiliation: Advanced Materials Engineering and Modelling Group, Faculty of Chemistry, Wroclaw University of Science and Technology , Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Samoc
mesh_terms: D000873:Anthracenes / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D009994:Osmolar Concentration; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000873:Anthracenes; D002412:Cations; D005456:Fluorescent Dyes; D004247:DNA