Examinando por Autor "Sanchez-Carnerero, Esther M."

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Coupling BODIPY with nitrogen-doped graphene quantum dots to address the water solubility of photosensitizers
(Royal Society of Chemistry, 2022-05-12) Gómez, I. Jennifer; Russo, Marina; Arcidiacono, Orazio A; Sanchez-Carnerero, Esther M.; Klán, Petr; Zajickova, Lenka
The potential of photodynamic therapy (PDT) applications is based primarily on the selection of suitable photosensitizers (PSs). However, highly efficient PSs producing singlet oxygen and other reactive oxygen species (ROS) often have poor water solubility and tend to aggregate in biological media. The most common alternative strategy to address the solubility of PSs is based on difficult-to-control encapsulation or conjugation to liposomes, micelles, or other nanoparticles via surface non-covalent interactions. Covalent functionalization remains relatively unexplored for common PSs. Here, we report a strategy to use highly efficient but poorly water-soluble BODIPY PSs connected to the surface of nitrogen-doped graphene quantum dots (NGQDs) through controlled covalent functionalization. These NGQD–BODIPY PSs do not aggregate in aqueous solutions and generate ROS upon irradiation with visible light, with singlet-oxygen production quantum yields up to 83%. In vitro fluorescence bioimaging was used to confirm that the PSs reside mostly in the cytoplasmic region of human cervical cancer cells (HeLa), and the system reduced the cell viability by B85% upon irradiation.
Detergent-modified catalytic and enzymomimetic activity of silver and palladium nanoparticles biotemplated by Pyrococcus furiosus ferritin
(ACADEMIC PRESS INC ELSEVIER SCIENCE, 2019-03-01) Peskova, Marie; Ilkovics, Ladislav; Hynek, David; Dostalova, Simona; Sanchez-Carnerero, Esther M.; Remes, Marek; Heger, Zbynek; Pekarik, Vladimir
Palladium and silver nanoparticles (NPs) anchored at the outer surface of ferritin form stable suspension of non-coated particles that possess several catalytic and enzymomimetic activities. These activities are strongly affected by detergents that significantly influence the reaction efficiency and specificity. Reductive dehalogenation of various azo dye substrates shows strong differences in reactivity for each substrate-detergent pair. Reductive dehalogenation is negatively influenced by cationic detergents while catalytic depropargylation is severely impaired by polyethylene oxide containing detergents that is an important finding in respect to potential biorthogonal applications. Moreover, Suzuki-Miyaura reaction is promoted by polyethylene oxide containing detergents but some of them also facilitate dehalogenation. Enzymomimetic peroxidase activity of silver NPs can be detected only in presence of sodium dodecyl sulfate (SDS) while peroxidase activity of palladium NPs is enhanced by SDS and sodium deoxycholate.
Fluorescent substrates for haloalkane dehalogenases: Novel probes for mechanistic studies and protein labeling
(Elsevier, 2020-04-08) Dockalova, Veronika; Sanchez-Carnerero, Esther M.; Dunajova, Zuzana; Palao, Eduardo; Slanska, Michaela; Buryska, Tomas; Damborsky, Jiri; Klán, Petr; Prokop, Zbynek
Haloalkane dehalogenases are enzymes that catalyze the cleavage of carbon-halogen bonds in halogenated compounds. They serve as model enzymes for studying structure–function relationships of >100.000 members of the α/β-hydrolase superfamily. Detailed kinetic analysis of their reaction is crucial for understanding the reaction mechanism and developing novel concepts in protein engineering. Fluorescent substrates, which change their fluorescence properties during a catalytic cycle, may serve as attractive molecular probes for studying the mechanism of enzyme catalysis. In this work, we present the development of the first fluorescent substrates for this enzyme family based on coumarin and BODIPY chromophores. Steady-state and pre-steady-state kinetics with two of the most active haloalkane dehalogenases, DmmA and LinB, revealed that both fluorescent substrates provided specificity constant two orders of magnitude higher (0.14–12.6 μM−1 s−1) than previously reported representative substrates for the haloalkane dehalogenase family (0.00005–0.014 μM−1 s−1). Stopped-flow fluorescence/FRET analysis enabled for the first time monitoring of all individual reaction steps within a single experiment: (i) substrate binding, (ii–iii) two subsequent chemical steps and (iv) product release. The newly introduced fluorescent molecules are potent probes for fast steady-state kinetic profiling. In combination with rapid mixing techniques, they provide highly valuable information about individual kinetic steps and mechanism of haloalkane dehalogenases. Additionally, these molecules offer high specificity and efficiency for protein labeling and can serve as probes for studying protein hydration and dynamics as well as potential markers for cell imaging.