- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Shedding light on biocatalysis: photoelectrochemical platforms for solar-driven biotransformation
摘要： Redox biocatalysis has come to the forefront because of its excellent catalytic efficiency, stereoselectivity, and environmental benignity. The green and sustainable biotransformation can be driven by photoelectrochemical (PEC) platforms where redox biocatalysis is coupled with photoelectrocatalysis. The main challenge is how to transfer photoexcited electrons to (or from) the enzyme redox centers for effective biotransformation using solar energy. This review commences with a conceptual discussion of biocatalytic PEC platforms and highlights recent advances in PEC-based biotransformation through cofactor regeneration or direct transfer of charge carriers to (or from) oxidoreductases on enzyme-conjugated electrodes. Finally, we address future perspectives and potential next steps in the vibrant field of biocatalytic photosynthesis.
关键词： photoelectrochemical,cofactor regeneration,biotransformation,redox enzymes,solar-driven,biocatalysis,direct electron transfer
更新于2025-09-23 15:22:29
-
A genetically encoded photosensitizer protein facilitates the rational design of a miniature photocatalytic CO2-reducing enzyme
摘要： Photosensitizers, which harness light energy to upgrade weak reductants to strong reductants, are pivotal components of the natural and artificial photosynthesis machineries. However, it has proved difficult to enhance and expand their functions through genetic engineering. Here we report a genetically encoded, 27 kDa photosensitizer protein (PSP), which facilitates the rational design of miniature photocatalytic CO2-reducing enzymes. Visible light drives PSP efficiently into a long-lived triplet excited state (PSP*), which reacts rapidly with reduced nicotinamide adenine dinucleotide to generate a super-reducing radical (PSP?), which is strong enough to reduce many CO2-reducing catalysts. We determined the three-dimensional structure of PSP? at 1.8 ? resolution by X-ray crystallography. Genetic engineering enabled the site-specific attachment of a nickel–terpyridine complex and the modular optimization of the photochemical properties of PSP, the chromophore/catalytic centre distance and the catalytic centre microenvironment, which culminated in a miniature photocatalytic CO2-reducing enzyme that has a CO2/CO conversion quantum efficiency of 2.6%.
关键词： quantum efficiency,photosensitizer protein,visible light,photocatalytic CO2-reducing enzymes,X-ray crystallography,nickel–terpyridine complex,genetic engineering
更新于2025-09-23 15:21:01
-
A Biomimetic Plasmonic Nanoreactor for Reliable Metabolite Detection
摘要： Reliable monitoring of metabolites in biofluids is critical for diagnosis, treatment, and long-term management of various diseases. Although widely used, existing enzymatic metabolite assays face challenges in clinical practice primarily due to the susceptibility of enzyme activity to external conditions and the low sensitivity of sensing strategies. Inspired by the micro/nanoscale confined catalytic environment in living cells, the coencapsulation of oxidoreductase and metal nanoparticles within the nanopores of macroporous silica foams to fabricate all-in-one bio-nanoreactors is reported herein for use in surface-enhanced Raman scattering (SERS)-based metabolic assays. The enhancement of catalytical activity and stability of enzyme against high temperatures, long-time storage or proteolytic agents are demonstrated. The nanoreactors recognize and catalyze oxidation of the metabolite, and provide ratiometric SERS response in the presence of the enzymatic by-product H2O2, enabling sensitive metabolite quantification in a “sample in and answer out” manner. The nanoreactor makes any oxidoreductase-responsible metabolite a candidate for quantitative SERS sensing, as shown for glucose and lactate. Glucose levels of patients with bacterial infection are accurately analyzed with only 20 μL of cerebrospinal fluids, indicating the potential application of the nanoreactor in vitro clinical testing.
关键词： metabolic assays,metabolic testing,macroporous silica foams,biomimetic nanoreactors,SERS biosensors,enzymes
更新于2025-09-23 15:19:57
-
Manipulating transition of a two-component Bose–Einstein condensate with a weak <i>δ</i> -shaped laser
摘要： Scyllo-inositol (SI), a stereoisomer of inositol, is regarded as a promising therapeutic agent for Alzheimer’s disease. Here, an in vitro cofactor-balance biotransformation for the production of SI from myo-inositol (MI) by thermophilic myo-inositol 2-dehydrogenase (IDH) and scyllo-inositol 2-dehydrogenase (SIDH) is presented. These two enzymes (i.e., IDH and SIDH from Geobacillus kaustophilus) are co-expressed in Escherichia coli BL21(DE3), and E. coli cells containing the two enzymes are permeabilized by heat treatment as whole-cell catalysts to convert MI to SI. After condition optimizations about permeabilized temperature, reaction temperature, and initial MI concentration, about 82 g L?1 of SI is produced from 250 g L?1 of MI within 24 h without any cofactor supplementation. This ?nal titer of SI produced is the highest to the authors’ limited knowledge. This study provides a promising method for the large-scale industrial production of SI.
关键词： whole-cell biotransformation,Scyllo-inositol,cofactor-free,cascade enzymes,Myo-inositol
更新于2025-09-23 15:19:57
-
Alleviating the toxicity of quantum dots to Phanerochaete chrysosporium by sodium hydrosulfide and cysteine
摘要： Quantum dots (QDs) have caused large challenges in clinical tests and biomedical applications due to their potential toxicity from nanosize effects and heavy metal components. In this study, the physiological responses of Phanerochaete chrysosporium (P. chrysosporium) to CdSe/ZnS QDs with either an inorganic sulfide NaHS or an organic sulfide cysteine as antidote have been investigated. Scanning electron microscope analysis showed that the hyphal structure and morphology of P. chrysosporium have obviously changed after exposure to 100 nM of COOH CdSe/ZnS 505, NH2 CdSe/ZnS 505, NH2 CdSe/ZnS 565, or NH2 CdSe/ZnS 625. Fourier transform infrared spectroscopy analysis indicated that the existence of hydroxyl, amino, and carboxyl groups on cell surface could possibly conduct the stabilization of QDs in an aqueous medium. However, after NaHS or cysteine treatment, the cell viability of P. chrysosporium exposed to CdSe/ZnS QDs increased as compared to control group, since NaHS and cysteine have assisted P. chrysosporium to alleviate oxidative damage by regulating lipid peroxidation and superoxide production. Meanwhile, NaHS and cysteine have also stimulated P. chrysosporium to produce more antioxidant enzymes (superoxide dismutase and catalase), which played significant roles in the defense system. In addition, NaHS and cysteine were used by P. chrysosporium as sulfide sources to promote the glutathione biosynthesis to relieve CdSe/ZnS QDs-induced oxidative stress. This work revealed that sulfide sources (NaHS and cysteine) exerted a strong positive effect in P. chrysosporium against the toxicity induced by CdSe/ZnS QDs.
关键词： Detoxification,Cysteine,CdSe/ZnS quantum dots,Sodium hydrosulfide,Antioxidant enzymes,Oxidative stress
更新于2025-09-23 15:19:57
-
Light-wavelength-based Quantitative Control of Dihydrofolate Reductase Activity Using Photochromic Isostere of Inhibitor
摘要： Photopharmacology has attracted research attention as a new tool to achieve the optical control of biomolecules following the methods of caged compounds and optogenetics. We have developed an efficient photopharmacological inhibitor, azoMTX, for Escherichia coli dihydrofolate reductase (eDHFR) by replacing some atoms of the original ligand, methotrexate, to obtain the photoisomerization property. This fine molecular design enabled the quick structural conversion between the active 'bent' Z-isomer and the inactive 'extended' E-isomer of azoMTX, and this property afforded quantitative control of the enzyme activity, depending on the wavelength of irradiated light. The real-time photoreversible control of enzyme activity was also achieved.
关键词： methotrexate,photochromism,enzymes,azobenzene,photopharmacology
更新于2025-09-19 17:15:36
-
Graphene Quantum Dot-Based Nanocomposites for Diagnosing Cancer Biomarker APE1 in Living Cells
摘要： As an essential DNA repair enzyme, apurinic/apyrimidinic endonuclease 1 (APE1) is overexpressed in most human cancers and is identified as a cancer diagnostic and predictive biomarker for cancer risk assessment, diagnosis, prognosis and prediction of treatment efficacy. Despite its importance in cancer, however, it is still a significant challenge nowadays to sense abundance variation and monitor enzymatic activity of this biomarker in living cells. Here, we report our construction of biocompatible functional nanocomposites, which are a combination of meticulously designed unimolecular DNA and fine-sized graphene quantum dots. Upon utilization of these nanocomposites as diagnostic probes, massive accumulation of fluorescence signal in living cells can be triggered by merely a small amount of cellular APE1 through repeated cycles of enzymatic catalysis. Most critically, our delicate structural designs assure that these graphene quantum dot-based nanocomposites are capable of sensing cancer biomarker APE1 in identical type of cells under different cell conditions and can be applied to multiple cancerous cells in highly sensitive and specific manners. This work not only brings about new methods for cytology-based cancer screening, but also lays down a general principle for fabricating diagnostic probes that target other endogenous biomarkers in living cells.
关键词： cancer diagnosis,biomarker,nanocomposites,DNA repair enzymes,graphene quantum dots
更新于2025-09-19 17:13:59
-
Characterization of Enzymatically Synthesized Titania Thin Films Using Positron Annihilation Spectroscopy Reveals Lowa??Cost Approach for Organic/Inorganic Photovoltaic Cells
摘要： A new method is developed to produce mesoporous titania thin films at room temperature using the enzyme papain in a dip-coating procedure, providing low-cost titania films in a sustainable manner. Quartz crystal microbalance, positron annihilation Doppler broadening and lifetime spectroscopy, scanning electron microscopy, and X-ray diffraction are used to determine the deposition and structural properties of the films. As-deposited films have low densities ρ ≈ 0.6 g cm?3, contain small micropores and proteins, and exhibit corrugated surfaces. Annealing at temperatures of 300 °C or higher leads to the destruction and evaporation of most of the organic material, resulting in a thickness decrease of 50–60%, more pure titania films with increased density, an increase in micropore size and a decrease in the concentration and size of atomic-scale vacancies. Up to 50 layers could be stacked, allowing easy control over the total layer thickness. Based on these titania films, first test devices consisting of natural dye-sensitized solar cells are produced, that show photovoltaic activity and indicate possibilities for low-cost, accessible, organic production of solar cells. Given the wide range of other applications for titania, this new method is a promising candidate for improving the fabrication of those products with respect to cost, sustainability, and production speed.
关键词： titania,biomineralization,enzymes,positron annihilation,photovoltaics
更新于2025-09-16 10:30:52
-
The Radioprotective Effects of Low-Intensity Laser Radiation on Rat Peripheral Blood Cells
摘要： The radioprotective effect of low-intensity laser radiation on blood cells was studied on Wistar rats. The following procedures was carried out: single total body γ-radiation (dose of 3 Gy) of rats; over-vein irradiation with continuous laser radiation (λ = 670 nm); and combined γ- and laser irradiation, which varied among different series of experiments according to the number of procedures and the energy density of the laser radiation (2.5 J/cm2, 1.25 J/cm2). The influence of γ- and laser radiation on the number of peripheral blood cells in rats, the activity of antioxidant defense enzymes (superoxide dismutase and catalase), and on the blood absorption spectra in regions sensitive to its oxygenation were studied. On the 4th day after γ-irradiation, the radioprotective effect of low-intensity laser radiation was manifested as an increase in the average number of leukocytes (up to 1.4 times) and lymphocytes (up to 1.8 times) in comparison with reduced γ-irradiation, in an increase in the relative lymphocyte proportion in the leukocyte population (up to 1.5 times), and in an increase in the activities of catalase and superoxide dismutase, which were decreased by the γ-irradiation. It was found that the changes in the number of erythrocytes, leukocytes, lymphocytes, and superoxide dismutase activity initiated by γ-radiation alone and by combined laser and γ-radiation differed in individual rats and depended on individual initial values. The molecular mechanisms of the observed photo-radiobiological effects are discussed.
关键词： low-intensity laser radiation,blood absorption spectra,γ-radiation,blood cells,antioxidant defense enzymes
更新于2025-09-11 14:15:04
-
Concurrent Asymmetric Reactions Combining Photocatalysis and Enzyme Catalysis: Direct Enantioselective Synthesis of 2,2-Disubstituted Indol-3-ones from 2-Arylindoles
摘要： The combination of photoredox and enzymatic catalysis for the direct asymmetric one-pot synthesis of 2,2-disubstituted indol-3-ones from 2-arylindoles through concurrent oxidization and alkylation reactions is described. 2-Arylindoles can be photocatalytically oxidized to 2-arylindol-3-one with subsequent enantioselective alkylation with ketones catalyzed by wheat germ lipase (WGL). The chiral quaternary carbon center at C2 of the indoles was directly constructed. This mode of concurrent photobiocatalysis provides a mild and powerful strategy for one-pot enantioselective synthesis of complex compounds. The experiments proved that other lipases containing structurally analogous catalytic triad in the active site also can catalyze the reaction in the same way. This reaction is the first example of combining the non-natural catalytic activity of hydrolases with visible-light catalysis for enantioselective organic synthesis and it does not require any cofactors.
关键词： photochemistry,enzymes,heterocycles,synthetic methods,asymmetric catalysis
更新于2025-09-10 09:29:36