RESUMEN
The SARS-CoV-2 main protease (Mpro) plays a crucial role in virus amplification and is an ideal target for antiviral drugs. Currently, authentic Mpro is prepared through two rounds of proteolytic cleavage. In this method, Mpro carries a self-cleavage site at the N-terminus and a protease cleavage site followed by an affinity tag at the C-terminus. This article proposes a novel method for producing authentic Mpro through single digestion. Mpro was constructed by fusing a His tag containing TEV protease cleavage sites at the N-terminus. The expressed recombinant protein was digested by TEV protease, and the generated protein had a decreased molecular weight and significantly increased activity, which was consistent with that of authentic Mpro generated by the previous method. These findings indicated that authentic Mpro was successfully obtained. Moreover, the substrate specificity of Mpro was investigated. Mpro had a strong preference for Phe at position the P2, which suggested that the S2 subsite was an outstanding target for designing inhibitors. This article also provides a reference for the preparation of Mpro for sudden coronavirus infection in the future.
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Proteasas 3C de Coronavirus , SARS-CoV-2 , SARS-CoV-2/enzimología , SARS-CoV-2/genética , Proteasas 3C de Coronavirus/genética , Proteasas 3C de Coronavirus/química , Proteasas 3C de Coronavirus/metabolismo , Especificidad por Sustrato , Humanos , Proteínas Recombinantes/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , COVID-19/virologíaRESUMEN
The main protease (Mpro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) plays a vital role in viral replication. To study the function of Mpro and screen inhibitors targeting Mpro, it is necessary to prepare high-purity and high-activity Mpro. In this study, four types of SARS-CoV-2 Mpros containing different termini were prepared, and their activities were determined successfully. The results showed that the activity of wild-type (WT) Mpro was the highest, and the additional residues at the N-terminus but not at the C-terminus had a major effect on the enzyme activity. To explain this, the alignment of structures of different forms of Mpro was determined, and the additional residues at the N-terminus were found to interfere with the formation of the substrate binding pocket. This study confirms the importance of the natural N-terminus to the activity of Mpro and suggests that WT-GPH6 (Mpro with eight additional residues at the C-terminus) can be used as a substitute for authentic Mpro to screen inhibitors. In short, this study provides a reference for the expression and purification of new coronaviruses confronted in the future.
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COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , COVID-19/genética , Cisteína Endopeptidasas/química , Inhibidores de Proteasas/farmacología , Antivirales/química , Simulación del Acoplamiento MolecularRESUMEN
3,4-Bisthiolated pyrroles constitute key cores in pyrrole-based semiconductors, and their electronic properties could be improved by the bisthio groups via the S-effect. Herein, a convenient method for the synthesis of 3,4-bisthiolated pyrroles has been developed through the AlCl3-catalyzed thiolation/cyclization of homopropargylic azides, and cyclic voltammetry and DFT calculations indicated that the desired 3,4-bisthiolated pyrroles had higher HOMO orbital energies and lower band gaps than the parent unsubstituted 2,5-diphenylpyrrole.
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Electrónica , Pirroles , Catálisis , Ciclización , Estructura MolecularRESUMEN
Herein, inorganic base K3PO4 promoted divergent synthesis of CF3-substituted allenes, cyclopentenes, alkynes, and fluorinated enynes via regioselective nucleophilic addition of carbon nucleophiles to 2-trifluoromethyl-1,3-enynes was developed. With the choice of different carbon nucleophiles, various fluorinated compounds could be obtained under K3PO4/DMF reaction system. When malononitriles were used as nucleophiles, CF3-substituted allenes, cyclopentenes, and alkynes could be obtained, respectively. By using 1,3-dicarbonyl compounds as nucleophiles, ring-monofluorinated 4H-pyrans could be prepared, and 1,1-difluoro-1,3-enynes could be furnished with the participation of diethyl malonate. Moreover, these five kinds of fluorinated allenes, alkenes, and enynes are valuable building blocks.
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Alquenos , Carbono , Catálisis , Alquinos , CiclopentanosRESUMEN
Symmetrical diaryl sulfides and diaryl disulfides have been efficiently and selectively constructed via the homocoupling of sodium arenesulfinates. The selectivity of products relied on the different reaction systems: symmetrical diaryl sulfides were predominately obtained under the Pd(OAc)2 catalysis, whereas symmetrical diaryl sulfides were exclusively yielded in the presence of the reductive Fe/HCl system.
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Disulfuros , Sulfuros , Catálisis , Estructura Molecular , SodioRESUMEN
The Rh(I)-catalyzed cascade formation of carbenoid followed by a carbonylative cyclization of silyl diynes has been established to achieve diverse ortho silyl-substituted phenolics, enabling access to fully substituted aryne precursors via a one-step fluorosulfurylation. The silyl mask on the termini of alkynes is demonstrated not only to suppress the undesired oxidation but also to control the selectivity of CO insertion. Straightforward access to fully substituted arynes was comprehensively established and applied for the efficient construction of polycyclic aromatic molecules.
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A facile method for the synthesis of 4-chalcogenylated pyrazoles has been developed via electrophilic chalcogenation/cyclization of α,ß-alkynic hydrazones. The cyclization of α,ß-alkynic aldehyde hydrazones could be induced by using either sulfenyl chloride or the S-electrophiles generated in situ from the reaction of NCS and arythiol. The developed method was successfully applied to the synthesis of the sulfenyl analogue of celecoxib.
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The asymmetric aza-Henry reaction of N-Boc imines and nitroalkanes was realized in the presence of 10 mol % dinuclear zinc-AzePhenol catalysts under ambient conditions. A variety of nitroamines were obtained in good yields (up to 97%) with excellent enantioselectivities (up to 99% ee) and high diasteroselectivity (up to 14:1 dr). Our protocol combined the operational simplicity and mild reaction conditions, thus making the process amenable for technical applications.
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An efficient method for the synthesis of 4-sulfenyl isoxazoles has been developed via AlCl3-mediated electrophilic cyclization/sulfenylation of 2-alkyn-1-one O-methyloximes. Remarkably, N-arylsulfanylsuccinimides are employed as electrophiles for the construction of 4-arylsulfanyl isoxazoles, and 4-alkylsulfanyl isoxazoles are accessed with dialkyl disulfides as electrophiles.
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Herein, we report a chemoselective P(NMe2)3-mediated reductive epoxidation of α-dicarbonyl compounds such as isatins, α-keto esters, and α-diketones with aldehydes and ketones, leading to an efficient synthesis of a wide range of highly functionalized unsymmetrical epoxides in moderate to excellent yields and diastereoselectivities. The Kukhtin-Ramirez adduct, which is exclusively generated in situ from an α-dicarbonyl compound and P(NMe2)3, plays a key role in governing the chemoselectivity. It represents the first practical synthesis of unsymmetrical epoxides via direct reductive epoxidation of two different carbonyl electrophiles and also complements the existing methods of generating epoxides.
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A new and convenient method for one-pot synthesis of α-arylhydrazo-ß-keto sulfones is developed via Cu (II)-catalyzed oxysulfonylation/diazenylation of alkenes. This four-component cascade reaction enables a series of α-arylhydrazo-ß-keto sulfone derivatives accessed from readily available alkenes, sulfinates, and diazonium salts under aerobic conditions. Furthermore, the 3-sulfonyl cinnolin-4(1 H)-one skeleton is successfully constructed from the corresponding α-arylhydrazo-ß-keto sulfone product under basic conditions.
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OBJECTIVES: To investigate the efficiency of a new cascade biocatalysis system for the conversion of R, S-ß-amino alcohols to enantiopure vicinal diol and ß-amino alcohol. RESULTS: An efficient cascade biocatalysis was achieved by combination of a transaminase, a carbonyl reductase and a cofactor regeneration system. An ee value of > 99% for 2-amino-2-phenylethanol and 1-phenyl-1, 2-ethanediol were simultaneously obtained with 50% conversion from R, S-2-amino-2-phenylethanol. The generality of the cascade biocatalysis was further demonstrated with the whole-cell approaches to convert 10-60 mM R, S-ß-amino alcohol to (R)- and (S)-diol and (R)- and (S)-ß-amino alcohol in 90-99% ee with 50-52% conversion. Preparative biotransformation was demonstrated at a 50 ml scale with mixed recombinant cells to give both (R)- and (S)-2-amino-2-phenylethanol and (R)- and (S)-1-phenyl-1, 2-ethanediol in > 99% ee and 40-42% isolated yield from racemic 2-amino-2-phenylethanol. CONCLUSIONS: This cascade biocatalysis system provides a new practical method for the simultaneous synthesis of optically pure vicinal diol and an ß-amino alcohol.
Asunto(s)
Oxidorreductasas de Alcohol/metabolismo , Amino Alcoholes/química , Amino Alcoholes/metabolismo , Biotecnología/métodos , Amino Alcoholes/análisis , Proteínas Bacterianas/metabolismo , Biocatálisis , Sistema Libre de Células , Escherichia coli/enzimología , Estereoisomerismo , Transaminasas/metabolismoRESUMEN
Switchable ortho/ipso-cyclization of N-arylpropynamides induced with N-sulfanylsuccinimides as general sulfur reagents is reported. In the presence of MeOH, para-fluoro N-arylpropynamides exclusively undergo the ipso-cyclization to give 3-sulfenyl azaspiro[4,5]trienones. Two kinds of bioactive heterocycles, benzothieno-[3,2-b]quinoline and -[2,3-c]quinolone, have been directly and efficiently prepared from the corresponding sulfenylated products.
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An acid-catalyzed intermolecular sulfenoamination reaction of alkenes is developed with sulfonamides as the nitrogen source and N-sulfanylsuccinimides as the sulfur source. This methodology provides a straightforward and general way to synthesize various ß-sulfonylamino sulfides with high regio- and diastereoselectivity. The developed method was coupled with intramolecular C-N coupling in a one-pot procedure to afford a series of dihydrobenzothiazine derivatives, a kind of important heterocycle used as biologically active compounds in medicinal chemistry.
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A simple and efficient metal-free sulfenylation/cyclization of aryl alkynoates has been developed, obtaining various 3-sulfenylated coumarins in moderate to excellent yields. In the presence of BF3·Et2O, the stable and readily accessible N-sulfanylsuccinimides were employed as electrophiles to induce the 6-endo-dig electrophilic cyclization of alkynoates. The reaction using substrates bearing a methoxy group on the phenoxy ring proceeded in an exclusively distinct pathway via either ipso sulfenylcyclization or sulfenylation of the phenoxy ring depending on the different locations of the methoxy substituent. The resulting 3-sulfenylated coumarins can be readily transformed to 3-sulfinylated or 3-sulfonylated coumarins under different oxidation conditions.
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Novel sulfur reagents N-vinylthio phthalimides (N-VTPs) have been employed as modular reagents for vinylthiolation, enabling the construction of aggregation-induced emission (AIE)-active tetraaryldivinyl sulfides (TADVSs) and diarylvinyl sulfides (DAVSs). Notably, TADVSs with sulfur insertion to ethene stators are reported as AIE luminogens (AIEgens) for the first time, and the corresponding photophysical properties and aggregated confirmation have been detailed for the demonstration of the AIE effect. A water-soluble TADVS with a quinolinium salt was prepared for cell imaging.
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A novel kind of S-alkynylthio sulfonate, which can be directly activated under visible-light irradiation, has been developed for the radical addition of multiple bond systems and radical coupling with diazonium salts under photocatalyst-free conditions. This strategy features a broad substrate scope, high regioselectivity, excellent tolerance of functional groups, and the late-stage modification of drugs. Experimental and theoretical mechanistic investigations gave reasonable insight into the photolysis of S-alkynylthio sulfonates and C-S bond formation.
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The reagent system of I2/K2CO3 could efficiently promote the oxazole synthesis from α-bromoketones and benzylamine derivatives in DMF. This method was not only suitable for 2,5-diaryl oxazole synthesis but also for 2,4,5-trisubstituted oxazole and 5-alkyl/alkenyl oxazole synthesis. Furthermore, this method was successfully applied to a one-step synthesis of a natural product halfordinol in 62% yield.
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Six new iridoid glucosides, patriridosides D-I (1-6), and one new iridoid, scabrol A (7), along with 12 known non-glycosidic and glycosidic iridoids (8-19), have been isolated from an ethanolic extract of the roots of Patrinia scabra. The cytotoxic activity of the isolated compounds against human cervical carcinoma HeLa cells and gastric carcinoma MNK-45 cells was evaluated using the MTT assay. Compounds 1, 4-6, 8, and 18 showed cytotoxic activities against the MNK-45 cell line with respective IC50 values of 15.6, 8.7, 9.4, 30.9, 23.8, and 11.2 µM, while only compound 10 showed cytotoxicity against the HeLa cell line, with an IC50 value of 24.5 µM.
Asunto(s)
Antineoplásicos Fitogénicos/aislamiento & purificación , Antineoplásicos Fitogénicos/farmacología , Glucósidos Iridoides/aislamiento & purificación , Glucósidos Iridoides/farmacología , Iridoides/aislamiento & purificación , Iridoides/farmacología , Patrinia/química , Antineoplásicos Fitogénicos/química , Línea Celular Tumoral , Ensayos de Selección de Medicamentos Antitumorales , Células HeLa , Humanos , Glucósidos Iridoides/química , Iridoides/química , Estructura Molecular , Raíces de Plantas/químicaRESUMEN
Differentiation between similarly reactive sites in molecules represents an ongoing challenge of organic synthesis. Herein we described one kind of versatile reagents, N-thiohydroxy succinimide esters (NTSEs), serving as both acyl and acylthio surrogates for the diverse synthesis of ketones, thioesters, amides, and acyl disulfides by selective cleavage of similarly reactive C-S and N-S bonds.