Quenching of Fluorescence

doi:10.1007/978-0-387-46312-4_8

Cited by 221 publications

(15 citation statements)

References 314 publications

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“…Due to the absorbance of ct-DNA at 290 and 355 nm, though very small, which are the excitation and emission wavelengths for procaine, respectively, we have corrected the fluorescence data for the inner filter effect using the method described in ESI (eqn (S1)) † and given in established literature. 26 The corrected fluorescence data were than quantified with the help of Stern–Volmer equation which is given as: “where F 0 and F are corrected fluorescence intensities in absence and presence of quencher (procaine), respectively, and K SV is Stern–Volmer constant and [Q] is the concentration of quencher, K q is the bimolecular quenching constant and τ 0 is life time of fluorophore in the absence of quencher which is equal to the 5.7 × 10 −9 s −1 ”. 26,27 When quenching of fluorophore occurs by a quencher the mechanism is either static or dynamic.…”

Section: Resultsmentioning

confidence: 99%

Comprehensive exploration of the anticancer activities of procaine and its binding with calf thymus DNA: a multi spectroscopic and molecular modelling study

et al. 2018

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Procaine is an anesthetic drug commonly administrated topically or intravenously for use in local anesthesia. Promisingly, some anticancer activities of procaine have also been reported. Therefore, the mechanism of interaction between anesthetic drug procaine with ct-DNA was determined collectively by means of various spectroscopic and molecular docking methods. Minor groove 1 : 1 binding of procaine to the ct-DNA was evidenced from absorption spectroscopy, fluorescence quenching, DNA melting, competitive binding measurements with EB and DAPI dyes, viscosity and CD spectroscopy together with molecular docking simulations and DFT calculations. Molecular docking on five different B-DNA structures (taken from the Protein Data Bank) shows that procaine binds in the AT rich region of all five B-DNA structures. Thermodynamic parameters, evaluated using van't Hoff's isotherm, shown that the interaction was feasible and the binding forces involved were hydrophobic as well as hydrogen bonding which were, further, confirmed by molecular docking. The frontier molecular orbitals (HOMO and LUMO) of procaine and DNA bases have been calculated by DFT method and the chemical potential (m), chemical hardness (h) and fraction number of electrons (DN) from procaine to DNA bases were evaluated, which have shown that procaine acts as an electron donor to the DNA bases. Simultaneously, anticancer activities of procaine alone and in combination with doxorubicin were observed on the MCF-7 breast cancer cell line. The results showed that the combined treatment with both procaine and doxorubicin enhanced the cytotoxic and apoptotic inducing potential of doxorubicin.

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Section: Resultsmentioning

confidence: 99%

Comprehensive exploration of the anticancer activities of procaine and its binding with calf thymus DNA: a multi spectroscopic and molecular modelling study

et al. 2018

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“…1a) provides means for monitoring the state of the aggregation probe in live cells by Fluorescence Lifetime Imaging Microscopy (FLIM). This methodology offers an accurate and absolute measure of the probe's state, free from the confounding effects of intensity calibrations and photo-bleaching 14,15,16 , thus removing the limits associated with the intensity-based readouts.…”

Section: Resultsmentioning

confidence: 99%

Stress-induced protein disaggregation in the Endoplasmic Reticulum catalysed by BiP

Melo

Farace

Konno

et al. 2021

Preprint

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Protein synthesis is supported by cellular machineries that ensure polypeptides fold to their native three-dimensional conformation with high fidelity whilst eliminating misfolded, aggregation-prone species. While protein aggregates can contribute to pathologies exemplified by Alzheimer's and Parkinson's diseases, their abundance is normally minimised by molecular chaperones such as HSP70/90, which promote native folding and drive the recycling of aberrantly folded species. Cytoplasmic chaperones (e.g. HSP70/40) can resolve insoluble protein aggregates should the preventive mechanisms falter. However, it is unknown whether an analogous disaggregation system is needed and exists in the Endoplasmic Reticulum (ER), where ~30% of the proteome is synthesised. Here we show that the ER of a variety of mammalian cell types, including neurons, is endowed with the capability to resolve protein aggregates that accumulate upon expression of metastable proteins. Utilising a purpose-developed protein aggregation probing system with a sub-organellar resolution, we observed steady-state aggregate accumulation in the ER. Strikingly, pharmacological induction of ER stress did not augment aggregates but rather stimulated their clearance within hours. We found that this disaggregation activity was catalysed by the stress-responsive ER molecular chaperone - BiP. Its elimination abolished the disaggregation activity in cells. Further, we reconstructed the disaggregation reaction in-vitro by a minimal system of ATP-fuelled BiP and its J-protein cofactor. These data reveal a hitherto unknown, non-redundant function of the ER stress response. Thus, our findings may facilitate the identification of aggregation-antagonising strategies and rationalising the age-dependent protein misfolding pathology.

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“…13 (8a-c, 8g, 9a-c, 9g; Table 4, entries 3-5,7,8-10,12). A survey of the literature revealed that electron-rich species, including substituted amino groups that can donate electrons to aromatic heterocycles (i.e., fluorophores), can act as potential fluorescence quenchers [66]. They are responsible for the formation of charge transfer complexes, which often return to the ground state without emitting a photon.…”

Section: Resultsmentioning

confidence: 99%

Efficient Synthesis of Novel 1,3,4-Oxadiazoles Bearing a 4-N,N-Dimethylaminoquinazoline Scaffold via Palladium-Catalyzed Suzuki Cross-Coupling Reactions

Wołek¹,

Werłos²,

Komander³

et al. 2020

Molecules

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Two series of novel (symmetrical and unsymmetrical) quinazolinylphenyl-1,3,4-oxadiazole derivatives were synthesized using palladium-catalyzed Suzuki cross-coupling reactions. The presented synthetic methodology is based on the use of bromine-substituted 2-phenyl-4-N,N-dimethylaminoquinazolines and either a boronic acid pinacol ester or a diboronic acid bis(pinacol) ester of 2,5-diphenyl-1,3,4-oxadiazole. The reactions are conducted in a two-phase solvent system in the presence of catalytic amounts of [1,1′-bis(diphenylphosphino)ferrocene]-dichloropalladium(II), sodium carbonate, and tetrabutylammonium bromide, which plays the role of a phase-transfer catalyst. The luminescence properties of the obtained compounds are discussed in the context of applying these compounds in optoelectronics. Specifically, two highly-conjugated final products: N,N-dimethyl-2-phenyl-6-(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl)quinazolin-4-amine (8f) and 6,6′-(4,4′-(1,3,4-oxadiazole-2,5-diyl)bis(4,1-phenylene))bis(N,N-dimethylquinazolin-4-amine (9f), which contain a 1,3,4-oxadiazole moiety connected to a quinazoline ring by a 1,4-phenylene linker at the 6 position, exhibit strong fluorescence emission and high quantum yields.

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Quenching of Fluorescence

Cited by 221 publications

References 314 publications

Comprehensive exploration of the anticancer activities of procaine and its binding with calf thymus DNA: a multi spectroscopic and molecular modelling study

Comprehensive exploration of the anticancer activities of procaine and its binding with calf thymus DNA: a multi spectroscopic and molecular modelling study

Stress-induced protein disaggregation in the Endoplasmic Reticulum catalysed by BiP

Efficient Synthesis of Novel 1,3,4-Oxadiazoles Bearing a 4-N,N-Dimethylaminoquinazoline Scaffold via Palladium-Catalyzed Suzuki Cross-Coupling Reactions

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