Synthesis and characterization of 4-ethoxymethylene-2-[1]-naphthyl-5(4H)-oxazolone and its fluorescent amino acid derivatives

Kóczán, György; Csı́k, Gabriella; Csámpai, Antal; Balog, Erika; Bősze, Szilvia; Sohár, Pàl; Hudecz, Ferenc

doi:10.1016/s0040-4020(01)00332-5

Cited by 32 publications

(14 citation statements)

References 12 publications

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“…The appropriate crystallization resulted to the pure target Z-isomers IIIa-d. Although oxazolones are well-known for their good fluorescent properties, 52 they are mainly used as intermediates. This limitation is caused by their hydrolytical instability in water and in other protic solvents, leading to ringopening 53 and loss of fluorescent properties.…”

Section: Methodsmentioning

confidence: 99%

Tuning the Excited-State Dynamics of GFP-Inspired Imidazolone Derivatives

et al. 2009

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The excited-state dynamics of five derivatives of the GFP-chromophore, which differ by the position and nature of their substituents, has been investigated in solvents of various viscosity and polarity and in rigid media using femtosecond-resolved spectroscopy. In polar solvents of low viscosity, like acetonitrile or methanol, the fluorescence decays of all compounds are multiexponential, with average lifetimes of the order of a few picoseconds, whereas in rigid matrices (polymer films and low temperature glasses), they are single exponential with lifetimes of the order of a few nanoseconds and fluorescence quantum yields close to unity. Global analysis of the fluorescence decays recorded at several wavelengths and of the transient absorption spectra reveals the presence of several excited-state populations with slightly different fluorescence and absorption spectra and with distinct lifetimes. These populations are attributed to the existence of multiple ground-state conformers. From the analysis of the dependence of the excited-state dynamics on the solvent and on the nature of the substituents, it follows that the nonradiative deactivation of all these excited chromophores involves an intramolecular coordinate with large amplitude motion. However, depending on the solvent and substituent, additional channels, namely, inter-and intramolecular hydrogen bond assisted nonradiative deactivation, are operative. This allows tuning of the excited-state lifetime of the chromophore. Finally, an ultrafast photoinduced intramolecular charge transfer is observed in polar solvents with one derivative bearing a dimethylaminophenyl substituent.

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Section: Methodsmentioning

confidence: 99%

Tuning the Excited-State Dynamics of GFP-Inspired Imidazolone Derivatives

et al. 2009

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“…45 Cys of the native sequence was replaced by an isoatomic Ser, which resulted in simplified synthesis and a chemically stable derivative. For receptor binding studies three peptides (naOx-18 QPLTSS-ER 25 , naOx-24 ERIDKQIR 31 and naOx-36 GISALRKETSN 46 ) labelled with the fluorescent marker 4-ethoxymethylene-2-(1)-naphthyl-5(4H)-oxazolone (naOx-OEt) (Bősze et al, 1997;Kóczán et al, 2001), were produced. For receptor binding studies three peptides (naOx-18 QPLTSS-ER 25 , naOx-24 ERIDKQIR 31 and naOx-36 GISALRKETSN 46 ) labelled with the fluorescent marker 4-ethoxymethylene-2-(1)-naphthyl-5(4H)-oxazolone (naOx-OEt) (Bősze et al, 1997;Kóczán et al, 2001), were produced.…”

Section: Synthetic Peptides and Their Conformation In Solutionmentioning

confidence: 99%

“…Three labelled peptide amides, (naOx-18 QPLTSSER 25 , naOx-24 ERIDKQIR 31 and naOx-36 GISALRKETNS 46 ) were synthesised by the incorporation of 4-etoxymethylene-2-(1)-naphthyl-5(4H)oxazolone (naOx-OEt) (Kóczán et al, 2001) at the N-terminal amino group of the peptide (Bősze et al, 1997). Briefly, peptide chains were assembled by solid phase methodology using Fmoc-strategy on Fmoc-2,4-dimethoxy-benzhydrylamine resin as described above.…”

Section: Synthesis Of Peptides Labelled With a Fluorophorementioning

confidence: 99%

“…In addition, the results of (i) solution conformation studies of peptides and (ii) binding experiments of selected pep-tides labelled with a new fluorophore (Kóczán et al, 2001) to soluble interleukin-6 receptor (sIL-6R) in the presence or absence of IL-6 are also presented. These indicate that even short synthetic peptides can be stimulatory (in the absence of IL-6) or inhibitory (in the presence of IL-6).…”

Section: Introductionmentioning

confidence: 99%

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Interleukin-6 N-Terminal Peptides Modulate the Expression of junB Protooncogene and the Production of Fibrinogen in HepG2 Cells

Bősze

Hudecz

Igaz

et al. 2003

Biological Chemistry

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Interleukin-6 (IL-6) is a helical cytokine exerting pleiotropic activities including the regulation of hematopoiesis, B cell activation and acute-phase reaction. The structure-function relationship of the molecule is the subject of intensive investigation using point and deletion mutants. Our objective was to analyse the role of the N-terminal 18-46 region in IL-6-mediated expression of junB protooncogene and fibrinogen production, reflecting the acute phase response, with synthetic overlapping peptides. mRNA expression of junB was monitored by competitive RT-PCR, while sandwich ELISA was used for the detection of fibrinogen in the supernatant of HepG2 human hepatoma cells. We found that even short synthetic octapeptides can be stimulatory (in the absence of IL-6) or inhibitory (in the presence of IL-6) in both assays. To establish the molecular mechanism by which synthetic peptides exert their biological effects electromobility shift assay was carried out using HepG2 nuclear extracts. Peptides inducing junB expression initiate gel shifts of STAT3/DNA complexes, which may indicate the involvement of this signal transduction pathway. Circular dicroism spectroscopy data suggest that 8-11-mer peptides representing different parts of the 18-46 region have a marked tendency to adopt ordered conformations in a water/trifluoroethanol (1:1 v/v) mixture. Competition studies with rhIL-6 and selected fluorophore-labelled peptides indicate the presence of more than one binding site on soluble IL-6 receptor. Considering the possible multiple etiologic role of IL-6 in the pathogenesis of various diseases, these peptides could be useful for dissection of IL-6 related biological effects.

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“…2-Phenyl-5(4H)-oxazolones are important intermediates in the synthesis of several molecules including amino acids, peptides, antimicrobial or antitumor compounds and heterocyclic precursors, as well as in biosensor coupling and photosensitive composition devices for proteins [6,7,8,9,10,11]. …”

Section: Introductionmentioning

confidence: 99%