title: A molecular approach to 4',6-diamidine-2-phenylindole (DAPI) photophysical behaviour at different pH values.
abstract: The photophysical mechanisms which determine the spectral properties and decay rates of 4',6-diamidine-2-phenylindole (DAPI) in solution and in association with nucleic acids have not yet been fully elucidated. We have performed steady-state and time-resolved fluorescence experiments on DAPI in a wide pH range to investigate the hypothesis that different ground-state conformations are responsible for the photophysical properties of the probe. Several excited-state mechanisms are investigated and it is concluded that among the proposed models, the hypothesis of ground-state heterogeneity with rapid interconversion among conformations is the only one consistent with the experiments in the entire pH range investigated.
authors.affiliation: Department of Physics, University of Illinois, Urbana-Champaign 61801.
authors.forename: M L
authors.initials: ML
authors.lastname: Barcellona
authors.forename: E
authors.initials: E
authors.lastname: Gratton
mesh_terms: D004247:DNA / Q000737:chemistry; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D007211:Indoles / Q000737:chemistry*; D011522:Protons; D013050:Spectrometry, Fluorescence
chemical_list: D005456:Fluorescent Dyes; D007211:Indoles; D011522:Protons; C007293:DAPI; D004247:DNA