title: Spectral fine tuning of cyanine dyes: electron donor-acceptor substituted analogues of thiazole orange.
abstract: The introduction of electron donor and acceptor groups at strategic locations on a fluorogenic cyanine dye allows fine-tuning of the absorption and emission spectra while preserving the ability of the dye to bind to biomolecular hosts such as double-stranded DNA and a single-chain antibody fragment originally selected for binding to the parent unsubstituted dye, thiazole orange (TO). The observed spectral shifts are consistent with calculated HOMO-LUMO energy gaps and reflect electron density localization on the quinoline half of TO in the LUMO. A dye bearing donating methoxy and withdrawing trifluoromethyl groups on the benzothiazole and quinoline rings, respectively, shifts the absorption spectrum to sufficiently longer wavelengths to allow excitation at green wavelengths as opposed to the parent dye, which is optimally excited in the blue.
authors.affiliation: Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA. army@cmu.edu.
authors.forename: Elizabeth E
authors.initials: EE
authors.lastname: Rastede
authors.forename: Matteus
authors.initials: M
authors.lastname: Tanha
authors.forename: David
authors.initials: D
authors.lastname: Yaron
authors.forename: Simon C
authors.initials: SC
authors.lastname: Watkins
authors.forename: Alan S
authors.initials: AS
authors.lastname: Waggoner
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Armitage
mesh_terms: D052160:Benzothiazoles / Q000138:chemical synthesis / Q000737:chemistry*; D004247:DNA / Q000737:chemistry; D004583:Electrons; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D008027:Light; D008856:Microscopy, Fluorescence; D008956:Models, Chemical; D015394:Molecular Structure; D055668:Photochemical Processes; D011506:Proteins / Q000737:chemistry; D011804:Quinolines / Q000138:chemical synthesis / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D052160:Benzothiazoles; D005456:Fluorescent Dyes; D011506:Proteins; D011804:Quinolines; C051000:thiazole orange; D004247:DNA