- Topology-Selective, Fluorescent “Light-Up” Probes for G-Quadruplex DNA Based on Photoinduced Electron Transfer
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Six novel probes were prepared by covalent attachment of a G4-DNA ligand (bis(quinolinium) pyridodicarboxamide; PDC) to various coumarin or pyrene fluorophores. In the absence of DNA, the fluorescence of all probes is quenched due to intramolecular photoinduced electron transfer (PET), as evidenced by photophysical and electrochemical studies, molecular modeling, and DFT calculations. All probes demonstrate similarly high thermal stabilization of various G4-DNA substrates belonging to different folding topologies, as assessed by fluorescence melting experiments; however, their fluorimetric response is strongly heterogeneous with respect to the structures of the probes and G4-DNA targets. Thus, the probes containing the 7-diethylaminocoumarin fluorophore demonstrate significant fluorescence enhancement in the presence of G4-DNA, with the strongest “light-up” response (20- to 180-fold) observed for antiparallel G4 structures as well as for hybrid G4 structures, formed by the variants of human telomeric sequence and capable of a conformation change to the antiparallel isoform. These results shed light on the influence of the linker and electronic properties of fluorophores on the efficiency of G4-DNA “light-up” probes operating via PET.
- Xie, Xiao,Reznichenko, Oksana,Chaput, Ludovic,Martin, Pascal,Teulade-Fichou, Marie-Paule,Granzhan, Anton
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supporting information
p. 12638 - 12651
(2018/08/01)
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- Fluorescently Labeled Amino Acids as Building Blocks for Bioactive Molecules
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A series of twelve fluorescently labeled amino acids were designed by assembling different coumarin, fluorescein, or nitrobenzo-furazan fluorophores with N-protected lysine or 2-aminopropionic acid. The synthesized amino acids were evaluated with regard to their spectroscopic properties. The easy introduction of the amino acids into peptides and peptidomimetics was exemplarily shown for one coumarin-labeled- amino acid.
- H?u?ler, Daniela,Gütschow, Michael
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p. 245 - 255
(2016/01/15)
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- Site Covalent Modification of Methionyl Peptides for the Production of FRET Complexes
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Flax cyclic peptides (orbitides, linusorbs (LOs)) [1-8-NαC],[1-MetO2]-linusorb B1 ([MetO2]-LO1) and [1-9-NαC],[1-MetO2]-linusorb B2 ([MetO2]-LO2) are biologically active. These LOs lack active nuclei commonly used in peptide modification. We have developed reactions to activate methionine methyl sulphide to produce stable derivatives. In these reactions, LOs are converted to sulfonium intermediates and subsequently to derivatives containing active nuclei while preserving their fundamental structures. The reaction conditions preserved cyclic peptide fundamental structure and organic solvent solubility. [Met]-LO1 and [Met]-LO2 analogues containing activated groups (-CN, -COOEt, and -NH2) in the form of methionine, methionine (S)-oxide, and methionine (S,S)-dioxide amino acids were synthesized and characterized by LCMS and 1D and 2D NMR spectroscopy. Coumarin orbitide complexes produced in this manner bind Eu3+ yielding FRET compounds that absorb energy through coumarin antennae and emit photons at lanthanide wavelengths.
- Jadhav, Pramodkumar D.,Shen, Jianheng,Sammynaiken, Ramaswami,Reaney, Martin J. T.
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p. 17023 - 17034
(2015/11/16)
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- Synthesis and evaluation of self-calibrating ratiometric viscosity sensors
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We describe the design, synthesis and fluorescent profile of a family of self-calibrating dyes that provide ratiometric measurements of fluid viscosity. The design is based on covalently linking a primary fluorophore (reference) that displays a viscosity-independent fluorescence emission with a secondary fluorophore (sensor) that exhibits a viscosity-sensitive fluorescence emission. Characterization of fluorescent properties was made with separate excitation of the units and through Resonance Energy Transfer from the reference to the sensor dye. The chemical structures of both fluorophores and the linker length have been evaluated in order to optimize the overall brightness and sensitivity of the viscosity measurements. We also present an application of such ratiometric dyes for the detection of membrane viscosity changes in a liposome model.
- Yoon, Hyung-Jo,Dakanali, Marianna,Lichlyter, Darcy,Chang, Willy M.,Nguyen, Karen A.,Nipper, Matthew E.,Haidekker, Mark A.,Theodorakis, Emmanuel A.
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supporting information; experimental part
p. 3530 - 3540
(2011/06/25)
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