The Fluorophore 4′,6‐Diamidino‐2‐phenylindole (DAPI) Induces DNA Folding in Long Double‐Stranded DNA |
| |
| Authors: | Dr. Maria Rosa Beccia Dr. Tarita Biver Alberto Pardini Jacopo Spinelli Prof. Fernando Secco Prof. Marcella Venturini Dr. Natalia Busto Vázquez Prof. Maria Pilar Lopez Cornejo Victoria Isabel Martin Herrera Prof. Rafael Prado Gotor |
| |
| Affiliation: | 1. Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via Risorgimento 35, 56126 Pisa (Italy), Fax: (+39)?050‐2219260;2. Departamento de Química, Universidad de Burgos, Plaza Misael Ba?uelos s.n., 09001 Burgos (Spain);3. Departamento de Química Física, University of Seville, C/Profesor García González s/n, 41012, Seville (Spain) |
| |
| Abstract: | DAPI (4′,6‐diamidino‐2‐phenylindole) is a widely used fluorescent dye, whose complicated binding features to DNAs and RNAs have been the object of debates and are still not fully understood. In this study, different approaches were employed, including binding equilibrium measurements (spectrofluorometry), melting experiments (spectrophotometry), viscometric measurements, circular dichroism, and T‐jump kinetic analyses; all data concur in shedding light on the complex mechanistic aspects of the binding mode of DAPI to natural DNA. Conditions are found that induce the mode of the DAPI/DNA interaction to change from groove binding to intercalation. Moreover, it is observed, for the first time, that DAPI is able to induce the formation of a rather compact polymer–dye adduct under particular conditions. The results suggest that this form is a folded or coiled DNA structure stabilized by DAPI dye bridges. |
| |
| Keywords: | coiling DNA structures groove binding intercalation reaction mechanisms |
|
|
