title: UV-Fluorescence correlation spectroscopy of 2-aminopurine.
abstract: We have built a fluorescence correlation spectroscopy (FCS) microscope for ultraviolet excitation (280-300 nm) and emission. With UV excitation the fluorescence of 'natural fluorophores' such as the modified nucleotide 2-aminopurine can be analyzed. The sensitivity of a natural fluorophore toward conformational changes can reveal dynamics in biomolecules. UV-FCS is well suited for detection of intensity fluctuations related to such conformational dynamics. Here we show UV-FCS measured on p-Quarterphenyl and on 2-aminopurine (2-AP). The triplet state rate constants and the excitation cross section for 2-AP were estimated to k23 = 1 x 10(6) s(-1), k31 = 3 x 10(5) s(-1), and sigma(exc) = 2 x 10(-17) cm2.
authors.affiliation: Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Wennmalm
authors.forename: H
authors.initials: H
authors.lastname: Blom
authors.forename: L
authors.initials: L
authors.lastname: Wallerman
authors.forename: R
authors.initials: R
authors.lastname: Rigler
mesh_terms: D015075:2-Aminopurine / Q000737:chemistry*; D001555:Benzene Derivatives / Q000737:chemistry; D004146:Dioxanes / Q000737:chemistry; D016011:Normal Distribution; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014364:Tryptophan / Q000737:chemistry; D014466:Ultraviolet Rays
chemical_list: D001555:Benzene Derivatives; D004146:Dioxanes; D012997:Solvents; D015075:2-Aminopurine; D014364:Tryptophan; C025223:1,4-dioxane