JACS Au最新文献

Hirsutanes are mushroom-derived sesquiterpenes with a characteristic 5-5-5 tricyclic ring skeleton. To date, more than 70 derivatives have been isolated from nature. In this study, we applied heterologous expression, in vitro enzymatic reactions, and biotransformation to characterize the function of nine enzymes involved in the synthesis of anhydroarthrosporone and six novel hirsutanes. The elucidated biosynthesis involves oxidative modifications of the A-ring followed by structural diversification of the B- and C-rings. Most importantly, biosynthetic pathways provide crucial insights into the classification and organization of isolated hirsutanes. We successfully classified 69 natural hirsutanes into three groups based on their A-ring modification patterns. Our classification covered 92% of the natural hirsutanes. A comprehensive understanding of their biosynthesis will provide opportunities to isolate structurally diverse hirsutanes using genetic engineering techniques.

Cationic amphiphiles have been demonstrated to be superior targeted antibacterial agents whose antibacterial activity exhibits a close relationship with their alkyl chain substituents. However, a systematic and deep investigation of the structure-property relationship is still pending. Meanwhile, cationic amphiphiles have a risk of accumulating in living mammalian cells, which poses a great threat to biosafety and clinical applications. In this study, a series of cationic amphiphilic aggregation-induced emission luminogens (AIEgens) with different alkyl chains (TPD-4, TPD-6, and TPD-12) have been developed with selective and variable antibacterial activity against Gram-positive bacteria depending on the alkyl chain length. Among them, TPD-6 with the intermediate alkyl chain length exhibited superior Gram-positive antibacterial performance. In addition, these cationic amphiphilic AIEgens had negligible invasiveness to mammalian cells. Molecular dynamics simulations revealed that the binding and deforming capabilities of the cationic amphiphilic AIEgens to the phospholipid bilayer of bacteria are responsible for their antibacterial activity. In vivo experiments indicated that TPD-6 also exhibited significant antibacterial and wound-healing abilities against Gram-positive bacteria.

Hirsutanes are mushroom-derived sesquiterpenes with a characteristic 5-5-5 tricyclic ring skeleton. To date, more than 70 derivatives have been isolated from nature. In this study, we applied heterologous expression, in vitro enzymatic reactions, and biotransformation to characterize the function of nine enzymes involved in the synthesis of anhydroarthrosporone and six novel hirsutanes. The elucidated biosynthesis involves oxidative modifications of the A-ring followed by structural diversification of the B- and C-rings. Most importantly, biosynthetic pathways provide crucial insights into the classification and organization of isolated hirsutanes. We successfully classified 69 natural hirsutanes into three groups based on their A-ring modification patterns. Our classification covered 92% of the natural hirsutanes. A comprehensive understanding of their biosynthesis will provide opportunities to isolate structurally diverse hirsutanes using genetic engineering techniques.

Cationic amphiphiles have been demonstrated to be superior targeted antibacterial agents whose antibacterial activity exhibits a close relationship with their alkyl chain substituents. However, a systematic and deep investigation of the structure–property relationship is still pending. Meanwhile, cationic amphiphiles have a risk of accumulating in living mammalian cells, which poses a great threat to biosafety and clinical applications. In this study, a series of cationic amphiphilic aggregation-induced emission luminogens (AIEgens) with different alkyl chains (TPD-4, TPD-6, and TPD-12) have been developed with selective and variable antibacterial activity against Gram-positive bacteria depending on the alkyl chain length. Among them, TPD-6 with the intermediate alkyl chain length exhibited superior Gram-positive antibacterial performance. In addition, these cationic amphiphilic AIEgens had negligible invasiveness to mammalian cells. Molecular dynamics simulations revealed that the binding and deforming capabilities of the cationic amphiphilic AIEgens to the phospholipid bilayer of bacteria are responsible for their antibacterial activity. In vivo experiments indicated that TPD-6 also exhibited significant antibacterial and wound-healing abilities against Gram-positive bacteria.

Glycoproteins, representing more than 50% of human proteins and most biopharmaceuticals, are crucial for regulating various biological processes. The complexity of multiple glycosylation sites often leads to incomplete sequence coverage and ambiguous glycan modification profiles. Here, we developed an integrative mass spectrometry-based approach for decoding unknown glycoproteins, which is featured with the combination of deglycosylation-mediated de novo sequencing with glycosylation site characterization. We utilized the enzymatic deglycosylation of N-/ O-glycans to achieve comprehensive sequence coverage. Additionally, EThcD fragmentation enables the identification of high-quality long peptides, facilitating precise protein assembly. We subsequently applied this method to de novo sequencing of the highly glycosylated therapeutic fusion protein Etanercept (Enbrel). We also sequenced three new tumor necrosis factor receptor:Fc-fusion biologics with largely unknown sequences, unveiling subtle distinctions in the primary sequences. Furthermore, we characterized N- and O-glycosylation modifications of these proteins at subunit, glycopeptide, and glycan levels. This strategy bridges the gap between the de novo sequencing and glycosylation modification, providing comprehensive information on the primary structure and glycosylation modifications for glycoproteins. Notably, our method could be a robust solution for accurate sequencing of the glycoproteins and has practical value not only in basic research but also in the biopharmaceutical industry.

The genetic information on organisms is stored in the cell nucleus in the form of higher-ordered DNA structures. Here, we use DNA framework nanostructures (DFNs) to simulate the compaction and stacking density of nucleosome DNA for precise conformational and structure determination, particularly the dynamic structural changes, preferential reaction regions, and sites of DFNs during the reactive oxygen species (ROS) reaction process. By developing an atomic force microscopy-based single-particle analysis (SPA) data reconstruction method to collect and reanalyze imaging information, we demonstrate that the geometric morphology of DFNs constrains their reaction kinetics with ROS, where local mechanical stress and regional base distribution are two key factors affecting their kinetics. Furthermore, we plot the reaction process diagram for ROS and DFNs, showing the reaction process and intermediate products with individual activation energies. This SPA method offers new research tools and insights for studying the dynamic changes of highly folded and organized DNA structural domains within the nucleus and helps to reveal the key mechanisms behind their functional differences in topologically associating domains.

Glycoproteins, representing more than 50% of human proteins and most biopharmaceuticals, are crucial for regulating various biological processes. The complexity of multiple glycosylation sites often leads to incomplete sequence coverage and ambiguous glycan modification profiles. Here, we developed an integrative mass spectrometry-based approach for decoding unknown glycoproteins, which is featured with the combination of deglycosylation-mediated de novo sequencing with glycosylation site characterization. We utilized the enzymatic deglycosylation of N-/ O-glycans to achieve comprehensive sequence coverage. Additionally, EThcD fragmentation enables the identification of high-quality long peptides, facilitating precise protein assembly. We subsequently applied this method to de novo sequencing of the highly glycosylated therapeutic fusion protein Etanercept (Enbrel). We also sequenced three new tumor necrosis factor receptor:Fc-fusion biologics with largely unknown sequences, unveiling subtle distinctions in the primary sequences. Furthermore, we characterized N- and O-glycosylation modifications of these proteins at subunit, glycopeptide, and glycan levels. This strategy bridges the gap between the de novo sequencing and glycosylation modification, providing comprehensive information on the primary structure and glycosylation modifications for glycoproteins. Notably, our method could be a robust solution for accurate sequencing of the glycoproteins and has practical value not only in basic research but also in the biopharmaceutical industry.

A general method for the catalytic asymmetric α-selenenylation of simple carbonyl compounds is lacking. Herein, a copper(I)-catalyzed enantioselective α-selenenylation of 2-acylimidazoles with electrophilic selenosulfonates is uncovered. The reaction enjoys the advantages of mild conditions, easy reaction protocol, and broad substrate scopes on both 2-acylimidazoles and selenosulfonates. Mechanistic studies reveal a pincer Cu(I)-(S,S)-Ph-BOPA complex as the active catalyst. Some traditional electrophilic selenenylation reagents, such as PhSeCl, PhSeSePh, and 2-(phenylselanyl)isoindoline-1,3-dione lead to inferior results in terms of both yield and enantioselectivity, highlighting the superiority of selenosulfonates. Finally, several transformations based on both the 2-acylimidazole group and the selenoether group are successfully carried out, demonstrating the synthetic utilities of the present methodology.

The prevalence of saturated azacycles within pharmaceuticals, natural products, and agrochemicals has prompted the development of many methods that modify their periphery. In contrast, technologies that interconvert distinct saturated azacyclic frameworks, which would uniquely facilitate access to underexplored chemical space, are highly limited. Existing approaches for modifying the core of azacycles usually require either the installation of reactive functionality, which must later be removed in subsequent steps, or the use of tailored substrates, limiting applicability to drug discovery. Herein, we report a borane-catalyzed contraction of saturated N-hydroxy azacycles. This transformation is uniquely enabling, allowing reorganization of the connectivity of the substrate without altering the molecular formula and generating products without vestigial functionality derived from auxiliary groups. The outcome of the reductive Stieglitz-type contraction can be attributed to a key stereoelectronic interaction enforced by geometric constraints, the mechanism of which we investigate using density functional theory. The method developed here enables the rapid late-stage reorganization of bioactive molecules featuring cyclic and linear amines. Overall, a general platform for saturated amine constitutional isomerization has been achieved.

A general method for the catalytic asymmetric α-selenenylation of simple carbonyl compounds is lacking. Herein, a copper(I)-catalyzed enantioselective α-selenenylation of 2-acylimidazoles with electrophilic selenosulfonates is uncovered. The reaction enjoys the advantages of mild conditions, easy reaction protocol, and broad substrate scopes on both 2-acylimidazoles and selenosulfonates. Mechanistic studies reveal a pincer Cu(I)-(S,S)-Ph-BOPA complex as the active catalyst. Some traditional electrophilic selenenylation reagents, such as PhSeCl, PhSeSePh, and 2-(phenylselanyl)isoindoline-1,3-dione lead to inferior results in terms of both yield and enantioselectivity, highlighting the superiority of selenosulfonates. Finally, several transformations based on both the 2-acylimidazole group and the selenoether group are successfully carried out, demonstrating the synthetic utilities of the present methodology.