title: 2-Aminopurine electronic structure and fluorescence properties in DNA.
abstract: 2-Aminopurine (2AP) fluorescence intensity and decay lifetimes have been used as indicators of nucleic acid geometry and dynamics. To characterize 2AP photophysics in the context of a DNA strand, time-dependent density functional theory is applied to 2AP stacked with two flanking nucleobases. Calculations show that 2AP in the trimers suffers a reduction in the oscillator strength of its low-lying pi-pi* 2AP-like allowed transition, manifested in a reduction of its radiative rate. Trimers also exhibit two or three lower-energy excited states (charge transfer states) that are predicted to facilitate nonradiative transitions from the fluorescent excited state.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St Louis, Missouri 63110, USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Jean
authors.forename: Kathleen B
authors.initials: KB
authors.lastname: Hall
mesh_terms: D015075:2-Aminopurine / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D019281:Dimerization; D004583:Electrons; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods; D006147:Guanine / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D011687:Purines / Q000737:chemistry; D011743:Pyrimidines / Q000737:chemistry; D013941:Thymine / Q000737:chemistry
chemical_list: D011687:Purines; D011743:Pyrimidines; D015075:2-Aminopurine; D006147:Guanine; D004247:DNA; C030986:pyrimidine; D013941:Thymine; C030985:purine