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The Journal of Physical Chemistry. A Nov 2022In this work, we studied the wavelength (520 or 350 nm) dependence of the photochemical decomposition of 1-phenyl-1-diazopropane () and 1-phenyl-1-propyl diazirine () by...
In this work, we studied the wavelength (520 or 350 nm) dependence of the photochemical decomposition of 1-phenyl-1-diazopropane () and 1-phenyl-1-propyl diazirine () by means of high-level quantum chemical calculations (CASSCF and MS-CASPT2) to obtain qualitative and quantitative results. It is found that the photochemistry of is governed by nonradiative deactivation processes that can involve one or two S/S conical intersections ( and ) depending on the wavelength of the radiation; is only accessible at the shortest wavelength. It is demonstrated that the main intermediate of the photochemistry of the titled compounds is 1-ethyl-1-phenyl carbene (). Upon irradiation of with the 520 nm light, the carbene is always generated in its ground state as closed-shell singlet carbene. In contrast, the 350 nm radiation can directly decompose into S carbene (open shell) and N when the conical intersection is avoided. Once the carbene is formed in the S state, it can experience excited state intramolecular proton transfer along a seam of crossing (ESIPT-SC) of the S and S states to yield the alkene derivative; that is, the proton transfer reaction takes places on a degenerate potential energy surface where the two electronic states have equal energy. In addition, it is found that absorbs at 350 nm (double excitations); therefore, there is another possible route that can induce as well a slightly different photochemistry in changing the wavelength of the radiation because the shortest wavelength (when it is intense enough) decreases the amount of available or generates a highly vibrationally excited state of the carbene; that is, after 350 nm excitation, the carbene intermediate can deactivate via radiation emission or can decay through a cascade of conical intersections to its first excited state (S), where ESIPT-SC is operative again.
PubMed: 36335481
DOI: 10.1021/acs.jpca.2c04816 -
Journal of Nanobiotechnology Sep 2023Calcium (Ca) is essential for mitochondrial homeostasis and function coordination, particularly in cancer cells that metabolize frequently to sustain their growth....
Calcium (Ca) is essential for mitochondrial homeostasis and function coordination, particularly in cancer cells that metabolize frequently to sustain their growth. Photochemistry mediated calcium overload has attracted lots of attention as an effective way to achieve tumor suppression. Herein, we developed a photonanomedicine to synergistically induce calcium overload via cell-surface photochemistry and thus tumor suppression. Specifically, the photosensitizer, protoporphyrin IX (PpIX) was loaded onto upconversion nanoparticles (UCNP), which was subsequently modified by a polymer bearing photo-crosslinking cinnamate (CA) groups. The resulting nanoparticle was further functionalized by anti-CD20 aptamers (Apt), to give photonanomedicine. The interaction between CD20 receptors and anti-CD20 aptamers allowed photonanomedicine to accurately attach onto the Raji cell surface after an intravenous injection. Following the local application of a 980 nm NIR laser, the photonanomedicine was able to capture the NIR light and convert it into ultraviolet (UV) light. On one hand, the converted UV light led the crosslinking of cinnamate groups in photonanomedicine, further stimulating the clustering of CD20 receptors and causing Ca influx. On the other hand, the UV light could simultaneously excited PpIX to generate reactive oxygen species (ROS) in situ to break down the integrity of cell membrane and lead to an influx of Ca. The synergistic Ca overload mediated by photonanomedicine exhibited an enhanced and superior anti-tumor efficacy. We believe this photonanomedicine expands the toolbox to manipulate intracellular Ca concentration and holds a great potential as an anti-tumor therapy.
Topics: Calcium; Photochemistry; Cell Membrane; Light; Cinnamates; Oligonucleotides
PubMed: 37726778
DOI: 10.1186/s12951-023-02090-z -
Biochemistry. Biokhimiia Jun 2015This review covers the properties of a retinal protein (ESR) from the psychrotrophic bacterium Exiguobacterium sibiricum that functions as a light-driven proton pump.... (Review)
Review
This review covers the properties of a retinal protein (ESR) from the psychrotrophic bacterium Exiguobacterium sibiricum that functions as a light-driven proton pump. The presence of a lysine residue at the position corresponding to intramolecular proton donor for the Schiff base represents a unique structural feature of ESR. We have shown that Lys96 successfully facilitates delivery of protons from the cytoplasmic surface to the Schiff base, thus acting as a proton donor in ESR. Since proton uptake during the photocycle precedes Schiff base reprotonation, we conclude that this residue is initially in the uncharged state and acquires a proton for a short time after Schiff base deprotonation and M intermediate formation. Involvement of Lys as a proton donor distinguishes ESR from the related retinal proteins - bacteriorhodopsin (BR), proteorhodopsin (PR), and xanthorhodopsin (XR), in which the donor function is performed by residues with a carboxyl side chain. Like other eubacterial proton pumps (PR and XR), ESR contains a histidine residue interacting with the proton acceptor Asp85. In contrast to PR, this interaction leads to shift of the acceptor's pKa to more acidic pH, thus providing its ability to function over a wide pH range. The presence of a strong H-bond between Asp85 and His57, the structure of the proton-conducting pathways from cytoplasmic surface to the Schiff base and to extracellular surface, and other properties of ESR were demonstrated by solving its three-dimensional structure, which revealed several differences from known structures of BR and XR. The structure of ESR, its photocycle, and proton transfer reactions are discussed in comparison with homologous retinal proteins.
Topics: Bacillales; Bacterial Proteins; Bacteriorhodopsins; Lysine; Photochemistry; Proton Pumps; Rhodopsins, Microbial
PubMed: 26531015
DOI: 10.1134/S000629791506005X -
Bioconjugate Chemistry Oct 2021Phase transition is a promising aspect of DNA as biopolymers. Anionic DNA oligonucleotides easily form complexes with cationic polypeptides such as polylysine, and...
Phase transition is a promising aspect of DNA as biopolymers. Anionic DNA oligonucleotides easily form complexes with cationic polypeptides such as polylysine, and duplex formation significantly influences their complexation and resulting microcompartments. In this study, phase transition of microcompartments containing DNA and polylysine was systematically induced by modulating duplex formation of arylazopyrazole-conjugated oligonucleotides with light. We demonstrated that UV irradiation destabilized DNA duplex and generated isotropic coacervates, while duplex stabilization by visible light irradiation caused the formation of liquid crystalline coacervates. This photocontrol of phase transition was highly repeatable, and similar changes were observed even after ten cycles of light irradiation. Our approach would provide a robust control layer to the development of tailor-made microcompartments.
Topics: DNA; Oligonucleotides; Photochemistry
PubMed: 34498851
DOI: 10.1021/acs.bioconjchem.1c00302 -
Medecine Sciences : M/S Mar 2015Numerous achievements in biology have resulted from the evolution of biophotonics, a general term describing the use of light in the study of living systems. Over the... (Review)
Review
Numerous achievements in biology have resulted from the evolution of biophotonics, a general term describing the use of light in the study of living systems. Over the last fifteen years, biophotonics has progressively blended with molecular genetics to give rise to optogenetics, a set of techniques enabling the functional study of genetically-defined cellular populations, compartments or processes with optical methods. In neuroscience, optogenetics allows real-time monitoring and control of the activity of specific neuronal populations in a wide range of animal models. This technical breakthrough provides a new level of sophistication in experimental approaches in the field of fundamental neuroscience, significantly enhancing our ability to understand the complexity of neuronal circuits.
Topics: Animals; Fluorescent Dyes; Gene Transfer Techniques; Humans; Neurons; Neurosciences; Opsins; Optogenetics; Photochemistry
PubMed: 25855283
DOI: 10.1051/medsci/20153103015 -
Angewandte Chemie (International Ed. in... Feb 2023Light passes through biological tissue, and so it is used for imaging biological processes in situ. Such observation is part of the very essence of science, but... (Review)
Review
Light passes through biological tissue, and so it is used for imaging biological processes in situ. Such observation is part of the very essence of science, but mechanistic understanding requires intervention. For more than 50 years a "second function" for light has emerged; namely, that of photochemical control. Caged compounds are biologically inert signaling molecules that are activated by light. These optical probes enable external instruction of biological processes by stimulation of an individual element in complex signaling cascades in its native environment. Cause and effect are linked directly in spatial, temporal, and frequency domains in a quantitative manner by their use. I provide a guide to the basic properties required to make effective caged compounds for the biological sciences.
Topics: Photochemistry; Signal Transduction; Biology
PubMed: 36646644
DOI: 10.1002/anie.202206083 -
Molecules (Basel, Switzerland) Nov 2020Non-proteinogenic amino acids have attracted tremendous interest for their essential applications in the realm of biology and chemistry. Recently, rising C-H... (Review)
Review
Non-proteinogenic amino acids have attracted tremendous interest for their essential applications in the realm of biology and chemistry. Recently, rising C-H functionalization has been considered an alternative powerful method for the direct synthesis of non-proteinogenic amino acids. Meanwhile, photochemistry has become popular for its predominant advantages of mild conditions and conservation of energy. Therefore, C-H functionalization and photochemistry have been merged to synthesize diverse non-proteinogenic amino acids in a mild and environmentally friendly way. In this review, the recent developments in the photo-mediated C-H functionalization of proteinogenic amino acids derivatives for the rapid synthesis of versatile non-proteinogenic amino acids are presented. Moreover, postulated mechanisms are also described wherever needed.
Topics: Amines; Amino Acids; Bromine; Carbon; Chemistry Techniques, Synthetic; Chemistry, Organic; Chlorine; Hydrogen; Peptides; Photochemistry
PubMed: 33198166
DOI: 10.3390/molecules25225270 -
Nature Communications Feb 2018Molecular logic gates are expected to play an important role on the way to information processing therapeutic agents, especially considering the wide variety of physical...
Molecular logic gates are expected to play an important role on the way to information processing therapeutic agents, especially considering the wide variety of physical and chemical responses that they can elicit in response to the inputs applied. Here, we show that a 1:2 demultiplexer based on a Zn-terpyridine-Bodipy conjugate with a quenched fluorescent emission, is efficient in photosensitized singlet oxygen generation as inferred from trap compound experiments and cell culture data. However, once the singlet oxygen generated by photosensitization triggers apoptotic response, the Zn complex then interacts with the exposed phosphatidylserine lipids in the external leaflet of the membrane bilayer, autonomously switching off singlet oxygen generation, and simultaneously switching on a bright emission response. This is the confirmatory signal of the cancer cell death by the action of molecular automaton and the confinement of unintended damage by excessive singlet oxygen production.
Topics: Apoptosis; Cell Line; Cell Membrane; Cells; Flow Cytometry; Humans; Phosphatidylserines; Photochemistry; Photosensitizing Agents; Singlet Oxygen; Zinc
PubMed: 29476048
DOI: 10.1038/s41467-018-03259-z -
Nature Chemistry Oct 2023Over the past few years, evidence has accrued that demonstrates that terrestrial photochemical reactions could have provided numerous (proto)biomolecules with...
Over the past few years, evidence has accrued that demonstrates that terrestrial photochemical reactions could have provided numerous (proto)biomolecules with implications for the origin of life. This chemistry simply relies on UV light, inorganic sulfur species and hydrogen cyanide. Recently, we reported that, under the same conditions, reduced phosphorus species, such as those delivered by meteorites, can be oxidized to orthophosphate, generating thiophosphate in the process. Here we describe an investigation of the properties of thiophosphate as well as additional possible means for its formation on primitive Earth. We show that several reported prebiotic reactions, including the photoreduction of thioamides, carbonyl groups and cyanohydrins, can be markedly improved, and that tetroses and pentoses can be accessed from hydrogen cyanide through a Kiliani-Fischer-type process without progressing to higher sugars. We also demonstrate that thiophosphate allows photochemical reductive aminations, and that thiophosphate chemistry allows a plausible prebiotic synthesis of the C moieties used in extant terpene and terpenoid biosynthesis, namely dimethylallyl alcohol and isopentenyl alcohol.
Topics: Photochemistry; Sugars; Hydrogen Cyanide; Terpenes; Phosphates
PubMed: 37443293
DOI: 10.1038/s41557-023-01251-9 -
Journal of the American Society For... Apr 2021Immunohistochemistry (IHC) combined with fluorescence microscopy provides an important and widely used tool for researchers and pathologists to image multiple biomarkers...
Immunohistochemistry (IHC) combined with fluorescence microscopy provides an important and widely used tool for researchers and pathologists to image multiple biomarkers in tissue specimens. However, multiplex IHC using standard fluorescence microscopy is generally limited to 3-5 different biomarkers, with hyperspectral or multispectral methods limited to 8. We report the development of a new technology based on novel photocleavable mass-tags (PC-MTs) for facile antibody labeling, which enables highly multiplexed IHC based on MALDI mass spectrometric imaging (MALDI-IHC). This approach significantly exceeds the multiplexity of both fluorescence- and previous cleavable mass-tag-based methods. Up to 12-plex MALDI-IHC was demonstrated on mouse brain, human tonsil, and breast cancer tissues specimens, reflecting the known molecular composition, anatomy, and pathology of the targeted biomarkers. Novel dual-labeled fluorescent PC-MT antibodies and label-free small-molecule mass spectrometric imaging greatly extend the capability of this new approach. MALDI-IHC shows promise for use in the fields of tissue pathology, tissue diagnostics, therapeutics, and precision medicine.
Topics: Animals; Biomarkers; Biomarkers, Tumor; Brain Chemistry; Breast Neoplasms; Female; Fluorescent Antibody Technique; Humans; Immunohistochemistry; In Situ Hybridization; Mice; Microspheres; Palatine Tonsil; Peptides; Photochemistry; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Streptavidin; Ultraviolet Rays
PubMed: 33631930
DOI: 10.1021/jasms.0c00473