-
Proceedings of the National Academy of... Feb 2020Rhodopsins are the most abundant light-harvesting proteins. A new family of rhodopsins, heliorhodopsins (HeRs), has recently been discovered. Unlike in the known...
Rhodopsins are the most abundant light-harvesting proteins. A new family of rhodopsins, heliorhodopsins (HeRs), has recently been discovered. Unlike in the known rhodopsins, in HeRs the N termini face the cytoplasm. The function of HeRs remains unknown. We present the structures of the bacterial HeR-48C12 in two states at the resolution of 1.5 Å, which highlight its remarkable difference from all known rhodopsins. The interior of HeR's extracellular part is completely hydrophobic, while the cytoplasmic part comprises a cavity (Schiff base cavity [SBC]) surrounded by charged amino acids and containing a cluster of water molecules, presumably being a primary proton acceptor from the Schiff base. At acidic pH, a planar triangular molecule (acetate) is present in the SBC. Structure-based bioinformatic analysis identified 10 subfamilies of HeRs, suggesting their diverse biological functions. The structures and available data suggest an enzymatic activity of HeR-48C12 subfamily and their possible involvement in fundamental redox biological processes.
Topics: Computational Biology; Hydrogen-Ion Concentration; Models, Molecular; Photolysis; Protein Conformation; Rhodopsins, Microbial
PubMed: 32034096
DOI: 10.1073/pnas.1915888117 -
Circulation Research Jan 2016
Topics: Action Potentials; Animals; Calcium Channels, L-Type; Calcium Signaling; Electrophysiologic Techniques, Cardiac; Female; Heart Rate; Heart Ventricles; Humans; Male; Microscopy, Fluorescence; Models, Cardiovascular; Myocytes, Cardiac; Photolysis; Sodium-Calcium Exchanger
PubMed: 26838308
DOI: 10.1161/CIRCRESAHA.115.308067 -
Molecules (Basel, Switzerland) Sep 2019Sonochemical oxidation of organic pollutants in an aqueous environment is considered to be a green process. This mode of degradation of organic pollutants in an aqueous... (Review)
Review
Sonochemical oxidation of organic pollutants in an aqueous environment is considered to be a green process. This mode of degradation of organic pollutants in an aqueous environment is considered to render reputable outcomes in terms of minimal chemical utilization and no need of extreme physical conditions. Indiscriminate discharge of toxic organic pollutants in an aqueous environment by anthropogenic activities has posed major health implications for both human and aquatic lives. Hence, numerous research endeavours are in progress to improve the efficiency of degradation and mineralization of organic contaminants. Being an extensively used advanced oxidation process, ultrasonic irradiation can be utilized for complete mineralization of persistent organic pollutants by coupling/integrating it with homogeneous and heterogeneous photocatalytic processes. In this regard, scientists have reported on sonophotocatalysis as an effective strategy towards the degradation of many toxic environmental pollutants. The combined effect of sonolysis and photocatalysis has been proved to enhance the production of high reactive-free radicals in aqueous medium which aid in the complete mineralization of organic pollutants. In this manuscript, we provide an overview on the ultrasound-based hybrid technologies for the degradation of organic pollutants in an aqueous environment.
Topics: Biodegradation, Environmental; Catalysis; Environmental Pollutants; Oxidation-Reduction; Photolysis; Ultrasonic Waves
PubMed: 31540329
DOI: 10.3390/molecules24183341 -
Molecules (Basel, Switzerland) Dec 2020Photocatalysis emerged in the last decades as a versatile technology, whose applications range from environmental remediation to hydrogen production, energy harvesting,...
Photocatalysis emerged in the last decades as a versatile technology, whose applications range from environmental remediation to hydrogen production, energy harvesting, and organic synthesis, with exciting examples also in medicine, electronics, and advanced functional materials [...].
Topics: Catalysis; Electronics; Environmental Restoration and Remediation; Photolysis; Polymers
PubMed: 33374553
DOI: 10.3390/molecules26010023 -
Molecules (Basel, Switzerland) Nov 2020Photocages have been successfully applied in cellular signaling studies for the controlled release of metabolites with high spatio-temporal resolution. Commonly,...
Photocages have been successfully applied in cellular signaling studies for the controlled release of metabolites with high spatio-temporal resolution. Commonly, coumarin photocages are activated by UV light and the quantum yields of uncaging are relatively low, which can limit their applications in vivo. Here, syntheses, the determination of the photophysical properties, and quantum chemical calculations of 7-diethylamino-4-hydroxymethyl-thiocoumarin (thio-DEACM) and caged adenine nucleotides are reported and compared to the widely used 7-diethylamino-4-hydroxymethyl-coumarin (DEACM) caging group. In this comparison, thio-DEACM stands out as a phosphate cage with improved photophysical properties, such as red-shifted absorption and significantly faster photolysis kinetics.
Topics: Adenosine Triphosphate; Coumarins; Fluorescence; Light; Nucleotides; Photolysis; Physical Phenomena
PubMed: 33203096
DOI: 10.3390/molecules25225325 -
Small (Weinheim An Der Bergstrasse,... Sep 2019Herein, the use of red blood cells (RBCs) as carriers of cytoplasmically interned phototherapeutic agents is described. Photolysis promotes drug release from the RBC...
Herein, the use of red blood cells (RBCs) as carriers of cytoplasmically interned phototherapeutic agents is described. Photolysis promotes drug release from the RBC carrier thereby providing the means to target specific diseased sites. This strategy is realized with a vitamin B12-taxane conjugate (B12-TAX), in which the drug is linked to the vitamin via a photolabile CoC bond. The conjugate is introduced into mouse RBCs (mRBCs) via a pore-forming/pore-resealing procedure and is cytoplasmically retained due to the membrane impermeability of B12. Photolysis separates the taxane from the B12 cytoplasmic anchor, enabling the drug to exit the RBC carrier. A covalently appended Cy5 antenna sensitizes the conjugate (Cy5-B12-TAX) to far red light, thereby circumventing the intense light absorbing properties of hemoglobin (350-600 nm). Microscopy and imaging flow cytometry reveal that Cy5-B12-TAX-loaded mRBCs act as drug carriers. Furthermore, intravital imaging of mice furnish a real time assessment of circulating phototherapeutic-loaded mRBCs as well as evidence of the targeted photorelease of the taxane upon photolysis. Histopathology confirms that drug release occurs in a well resolved spatiotemporal fashion. Finally, acoustic angiography is employed to assess the consequences of taxane release at the tumor site in Nu/Nu-tumor-bearing mice.
Topics: Animals; Bridged-Ring Compounds; Drug Carriers; Drug Delivery Systems; Erythrocytes; Female; Flow Cytometry; Humans; Mice; Photolysis; Prodrugs; Taxoids; Vitamin B 12
PubMed: 31353802
DOI: 10.1002/smll.201901442 -
Nature Methods Oct 2018
Topics: Fluorescence; HeLa Cells; Humans; Microscopy, Fluorescence; Oxidation-Reduction; Photochemical Processes; Photolysis
PubMed: 30275592
DOI: 10.1038/s41592-018-0145-5 -
International Journal of Molecular... Apr 2021Photodegradation of the aqueous solutions of acetylsalicylic acid, in the absence (ASA) and the presence of excipients (ASE), is demonstrated by the photoluminescence...
Photodegradation of the aqueous solutions of acetylsalicylic acid, in the absence (ASA) and the presence of excipients (ASE), is demonstrated by the photoluminescence (PL). A shift of the PL bands from 342 and 338 nm to 358 and 361-397 nm for ASA and ASE in solid state and as aqueous solutions was reported. By exposure of the solution of ASA 0.3 M to UV light, a decrease in the PL band intensity was highlighted. This behavior was revealed for ASA in the presence of phosphate buffer (PB) having the pH equal to 6.4, 7, and 8 or by the interaction with NaOH 0.3 M. A different behavior was reported in the case of ASE. In the presence of PB, an increase in the intensity of the PL band of ASE simultaneously with a change of the ratio between the intensities of the bands at 361-364 and 394-397 nm was highlighted. The differences between PL spectra of ASA and ASE have their origin in the presence of salicylic acid (SAL). The interaction of ASE with NaOH induces a shift of the PL band at 405-407 nm. Arguments for the reaction of ASA with NaOH are shown by Raman scattering and FTIR spectroscopy.
Topics: Aspirin; Cadmium Compounds; Luminescence; Photolysis; Quantum Dots; Solutions; Spectrum Analysis, Raman; Ultraviolet Rays; Water
PubMed: 33919943
DOI: 10.3390/ijms22084046 -
The Journal of Organic Chemistry Jan 2022Two fluorophores bound with a short photoreactive bridge are fascinating structures and remained unexplored. To investigate the synthesis and photolysis of such dyes, we...
Two fluorophores bound with a short photoreactive bridge are fascinating structures and remained unexplored. To investigate the synthesis and photolysis of such dyes, we linked two rhodamine dyes via a diazoketone bridge (-COCN-) attached to position 5' or 6' of the pendant phenyl rings. For that, the mixture of 5'- or 6'-bromo derivatives of the parent dye was prepared, transformed into 1,2-diarylacetylenes, hydrated to 1,2-diarylethanones, and converted to diazoketones ArCOCNAr. The high performance liquid chromatography (HPLC) separation gave four individual regioisomers of ArCOCNAr. Photolysis of the model compound─CHCOCNCH─in aqueous acetonitrile at pH 7.3 and under irradiation with 365 nm light provided diphenylacetic acid amide (Wolff rearrangement). However, under the same conditions, ArCOCNAr gave mainly α-diketones ArCOCOAr. The migration ability of the very bulky dye residues was low, and the Wolff rearrangement did not occur. We observed only moderate fluorescence increase, which may be explained by the insufficient quenching ability of diazoketone bridge (-COCN-) and its transformation into another (weaker) quencher, 1,2-diarylethane-1,2-dione.
Topics: Fluorescent Dyes; Photolysis; Rhodamines; Spectrometry, Fluorescence; Water
PubMed: 34919387
DOI: 10.1021/acs.joc.1c01721 -
Molecules (Basel, Switzerland) Feb 2020The exceptional reactivity of the azide group makes organic azides a highly versatile family of compounds in chemistry and the material sciences. One of the most... (Review)
Review
The exceptional reactivity of the azide group makes organic azides a highly versatile family of compounds in chemistry and the material sciences. One of the most prominent reactions employing organic azides is the regioselective copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition with alkynes yielding 1,2,3-triazoles. Other named reactions include the Staudinger reduction, the aza-Wittig reaction, and the Curtius rearrangement. The popularity of organic azides in material sciences is mostly based on their propensity to release nitrogen by thermal activation or photolysis. On the one hand, this scission reaction is accompanied with a considerable output of energy, making them interesting as highly energetic materials. On the other hand, it produces highly reactive nitrenes that show extraordinary efficiency in polymer crosslinking, a process used to alter the physical properties of polymers and to boost efficiencies of polymer-based devices such as membrane fuel cells, organic solar cells (OSCs), light-emitting diodes (LEDs), and organic field-effect transistors (OFETs). Thermosets are also suitable application areas. In most cases, organic azides with multiple azide functions are employed which can either be small molecules or oligo- and polymers. This review focuses on nitrene-based applications of multivalent organic azides in the material and life sciences.
Topics: Alkynes; Azides; Catalysis; Cross-Linking Reagents; Cycloaddition Reaction; Humans; Materials Science; Molecular Structure; Nitrogen; Photochemical Processes; Photolysis; Triazoles
PubMed: 32102403
DOI: 10.3390/molecules25041009