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Mitochondrial biogenesis is the process of generating new mitochondria to maintain cellular homeostasis. Here, we report that viruses exploit mitochondrial biogenesis to antagonize innate antiviral immunity. We found that nuclear respiratory factor-1 (NRF1), a vital transcriptional factor involved in nuclear-mitochondrial interactions, is essential for RNA (VSV) or DNA (HSV-1) virus-induced mitochondrial biogenesis. NRF1 deficiency resulted in enhanced innate immunity, a diminished viral load, and morbidity in mice. Mechanistically, the inhibition of NRF1-mediated mitochondrial biogenesis aggravated virus-induced mitochondrial damage, promoted the release of mitochondrial DNA (mtDNA), increased the production of mitochondrial reactive oxygen species (mtROS), and activated the innate immune response. Notably, virus-activated kinase TBK1 phosphorylated NRF1 at Ser318 and thereby triggered the inactivation of the NRF1-TFAM axis during HSV-1 infection. A knock-in (KI) strategy that mimicked TBK1-NRF1 signaling revealed that interrupting the TBK1-NRF1 connection ablated mtDNA release and thereby attenuated the HSV-1-induced innate antiviral response. Our study reveals a previously unidentified antiviral mechanism that utilizes a NRF1-mediated negative feedback loop to modulate mitochondrial biogenesis and antagonize innate immune response.
Assuntos
Antivirais , Biogênese de Organelas , Animais , Camundongos , DNA Mitocondrial/genética , Imunidade Inata , Fator 1 Nuclear Respiratório/genéticaRESUMO
Morphological profiling is a valuable tool in phenotypic drug discovery. The advent of high-throughput automated imaging has enabled the capturing of a wide range of morphological features of cells or organisms in response to perturbations at the single-cell resolution. Concurrently, significant advances in machine learning and deep learning, especially in computer vision, have led to substantial improvements in analyzing large-scale high-content images at high throughput. These efforts have facilitated understanding of compound mechanism of action, drug repurposing, characterization of cell morphodynamics under perturbation, and ultimately contributing to the development of novel therapeutics. In this review, we provide a comprehensive overview of the recent advances in the field of morphological profiling. We summarize the image profiling analysis workflow, survey a broad spectrum of analysis strategies encompassing feature engineering- and deep learning-based approaches, and introduce publicly available benchmark datasets. We place a particular emphasis on the application of deep learning in this pipeline, covering cell segmentation, image representation learning, and multimodal learning. Additionally, we illuminate the application of morphological profiling in phenotypic drug discovery and highlight potential challenges and opportunities in this field.
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Aprendizado Profundo , Descoberta de Drogas , Descoberta de Drogas/métodos , Humanos , Processamento de Imagem Assistida por Computador/métodos , Aprendizado de MáquinaRESUMO
Synchronized ferroptosis contributes to nephron loss in acute kidney injury (AKI). However, the propagation signals and the underlying mechanisms of the synchronized ferroptosis for renal tubular injury remain unresolved. Here we report that platelet-activating factor (PAF) and PAF-like phospholipids (PAF-LPLs) mediated synchronized ferroptosis and contributed to AKI. The emergence of PAF and PAF-LPLs in ferroptosis caused the instability of biomembranes and signaled the cell death of neighboring cells. This cascade could be suppressed by PAF-acetylhydrolase (II) (PAFAH2) or by addition of antibodies against PAF. Genetic knockout or pharmacological inhibition of PAFAH2 increased PAF production, augmented synchronized ferroptosis and exacerbated ischemia/reperfusion (I/R)-induced AKI. Notably, intravenous administration of wild-type PAFAH2 protein, but not its enzymatically inactive mutants, prevented synchronized tubular cell death, nephron loss and AKI. Our findings offer an insight into the mechanisms of synchronized ferroptosis and suggest a possibility for the preventive intervention of AKI.
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Injúria Renal Aguda , Ferroptose , Injúria Renal Aguda/metabolismo , Injúria Renal Aguda/patologia , Injúria Renal Aguda/tratamento farmacológico , Ferroptose/efeitos dos fármacos , Animais , Camundongos , Camundongos Endogâmicos C57BL , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/patologia , Fator de Ativação de Plaquetas/metabolismo , Camundongos Knockout , Humanos , MasculinoRESUMO
Intrinsically disordered proteins (IDPs) SAID1/2 are hypothetic dentin sialophosphoprotein-like proteins, but their true functions are unknown. Here, we identified SAID1/2 as negative regulators of SERRATE (SE), a core factor in miRNA biogenesis complex (microprocessor). Loss-of-function double mutants of said1; said2 caused pleiotropic developmental defects and thousands of differentially expressed genes that partially overlapped with those in se. said1; said2 also displayed increased assembly of microprocessor and elevated accumulation of microRNAs (miRNAs). Mechanistically, SAID1/2 promote pre-mRNA processing 4 kinase A-mediated phosphorylation of SE, causing its degradation in vivo. Unexpectedly, SAID1/2 have strong binding affinity to hairpin-structured pri-miRNAs and can sequester them from SE. Moreover, SAID1/2 directly inhibit pri-miRNA processing by microprocessor in vitro. Whereas SAID1/2 did not impact SE subcellular compartmentation, the proteins themselves exhibited liquid-liquid phase condensation that is nucleated on SE. Thus, we propose that SAID1/2 reduce miRNA production through hijacking pri-miRNAs to prevent microprocessor activity while promoting SE phosphorylation and its destabilization in Arabidopsis.
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Proteínas de Arabidopsis , Arabidopsis , Proteínas Intrinsicamente Desordenadas , MicroRNAs , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas Intrinsicamente Desordenadas/genética , Proteínas Intrinsicamente Desordenadas/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Ligação a RNA/metabolismo , Processamento Pós-Transcricional do RNA , MicroRNAs/metabolismo , Ribonuclease III/metabolismo , Regulação da Expressão Gênica de PlantasRESUMO
The mixed-lineage leukemia (MLL)-AF10 fusion oncoprotein recruits DOT1L to the homeobox A (HOXA) gene cluster through its octapeptide motif leucine zipper (OM-LZ), thereby inducing and maintaining the MLL-AF10-associated leukemogenesis. However, the recognition mechanism between DOT1L and MLL-AF10 is unclear. Here, we present the crystal structures of both apo AF10OM-LZ and its complex with the coiled-coil domain of DOT1L. Disruption of the DOT1L-AF10 interface abrogates MLL-AF10-associated leukemic transformation. We further show that zinc stabilizes the DOT1L-AF10 complex and may be involved in the regulation of the HOXA gene expression. Our studies may also pave the way for the rational design of therapeutic drugs against MLL-rearranged leukemia.
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Transformação Celular Neoplásica/patologia , Metiltransferases , Modelos Moleculares , Proteína de Leucina Linfoide-Mieloide , Fatores de Transcrição , Cristalização , Regulação Neoplásica da Expressão Gênica , Histona-Lisina N-Metiltransferase , Proteínas de Homeodomínio/genética , Humanos , Metiltransferases/química , Metiltransferases/metabolismo , Proteína de Leucina Linfoide-Mieloide/química , Proteína de Leucina Linfoide-Mieloide/metabolismo , Ligação Proteica , Domínios Proteicos , Estrutura Quaternária de Proteína , Relação Estrutura-Atividade , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo , Zinco/químicaRESUMO
Although substantial efforts have been made using graph neural networks (GNNs) for artificial intelligence (AI)-driven drug discovery, effective molecular representation learning remains an open challenge, especially in the case of insufficient labeled molecules. Recent studies suggest that big GNN models pre-trained by self-supervised learning on unlabeled datasets enable better transfer performance in downstream molecular property prediction tasks. However, the approaches in these studies require multiple complex self-supervised tasks and large-scale datasets , which are time-consuming, computationally expensive and difficult to pre-train end-to-end. Here, we design a simple yet effective self-supervised strategy to simultaneously learn local and global information about molecules, and further propose a novel bi-branch masked graph transformer autoencoder (BatmanNet) to learn molecular representations. BatmanNet features two tailored complementary and asymmetric graph autoencoders to reconstruct the missing nodes and edges, respectively, from a masked molecular graph. With this design, BatmanNet can effectively capture the underlying structure and semantic information of molecules, thus improving the performance of molecular representation. BatmanNet achieves state-of-the-art results for multiple drug discovery tasks, including molecular properties prediction, drug-drug interaction and drug-target interaction, on 13 benchmark datasets, demonstrating its great potential and superiority in molecular representation learning.
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Inteligência Artificial , Benchmarking , Sistemas de Liberação de Medicamentos , Descoberta de Drogas , Redes Neurais de ComputaçãoRESUMO
Plant viruses have multiple strategies to counter and evade the host's antiviral immune response. However, limited research has been conducted on the antiviral defense mechanisms commonly targeted by distinct types of plant viruses. In this study, we discovered that NUCLEAR FACTOR-YC (NF-YC) and NUCLEAR FACTOR-YA (NF-YA), 2 essential components of the NF-Y complex, were commonly targeted by viral proteins encoded by 2 different rice (Oryza sativa L.) viruses, rice stripe virus (RSV, Tenuivirus) and southern rice black streaked dwarf virus (SRBSDV, Fijivirus). In vitro and in vivo experiments showed that OsNF-YCs associate with OsNF-YAs and inhibit their transcriptional activation activity, resulting in the suppression of OsNF-YA-mediated plant susceptibility to rice viruses. Different viral proteins RSV P2 and SRBSDV SP8 directly disrupted the association of OsNF-YCs with OsNF-YAs, thereby suppressing the antiviral defense mediated by OsNF-YCs. These findings suggest an approach for conferring broad-spectrum disease resistance in rice and reveal a common mechanism employed by viral proteins to evade the host's antiviral defense by hindering the antiviral capabilities of OsNF-YCs.
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Oryza , Doenças das Plantas , Imunidade Vegetal , Proteínas de Plantas , Reoviridae , Tenuivirus , Proteínas Virais , Oryza/virologia , Oryza/imunologia , Oryza/genética , Doenças das Plantas/virologia , Doenças das Plantas/imunologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/imunologia , Proteínas Virais/metabolismo , Proteínas Virais/genética , Proteínas Virais/imunologia , Tenuivirus/fisiologia , Tenuivirus/patogenicidade , Vírus de Plantas/fisiologia , Fator de Ligação a CCAAT/metabolismo , Fator de Ligação a CCAAT/genética , Resistência à Doença/genéticaRESUMO
Late-stage functionalization (LSF) constitutes a powerful strategy for the assembly or diversification of novel molecular entities with improved physicochemical or biological activities. LSF can thus greatly accelerate the development of medicinally relevant compounds, crop protecting agents, and functional materials. Electrochemical molecular synthesis has emerged as an environmentally friendly platform for the transformation of organic compounds. Over the past decade, electrochemical late-stage functionalization (eLSF) has gained major momentum, which is summarized herein up to February 2023.
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Ferroptosis is an iron-dependent programmed necrosis characterized by glutathione (GSH) depletion and lipid peroxidation (LPO). Armed with both the pro- and antiferroptosis machineries, mitochondria play a central role in ferroptosis. However, how mitochondria sense the stress to activate ferroptosis under (patho-)physiological settings remains incompletely understood. Here, we show that FUN14 domain-containing 2, also known as HCBP6 (FUNDC2), a highly conserved and ubiquitously expressed mitochondrial outer membrane protein, regulates ferroptosis and contributes to doxorubicin (DOX)-induced cardiomyopathy. We showed that knockout of FUNDC2 protected mice from DOX-induced cardiac injury by preventing ferroptosis. Mechanistic studies reveal that FUNDC2 interacts with SLC25A11, the mitochondrial glutathione transporter, to regulate mitoGSH levels. Specifically, knockdown of SLC25A11 in FUNDC2-knockout (KO) cells reduced mitoGSH and augmented erasin-induced ferroptosis. FUNDC2 also affected the stability of both SLC25A11 and glutathione peroxidase 4 (GPX4), key regulators for ferroptosis. Our results demonstrate that FUNDC2 modulates ferroptotic stress via regulating mitoGSH and further support a therapeutic strategy of cardioprotection by preventing mitoGSH depletion and ferroptosis.
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Cardiomiopatias , Ferroptose , Animais , Cardiomiopatias/metabolismo , Doxorrubicina/metabolismo , Ferroptose/genética , Glutationa/metabolismo , Peroxidação de Lipídeos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Membranas Mitocondriais/metabolismoRESUMO
BACKGROUND: Recent studies have shown that several long non-coding RNAs (lncRNAs) in the placenta are associated with preeclampsia (PE). However, the extent to which lncRNAs may contribute to the pathological progression of PE is unclear. RESULTS: Here, we report a hierarchical regulatory network involved in early-onset severe PE (EOSPE). We have carried out transcriptome sequencing on the placentae from patients and normal subjects to identify the differentially expressed genes (DEGs), including some lncRNAs (DElncRNAs). We then constructed a high-quality hierarchical regulatory network of lncRNAs, transcription factors (TFs), and target DEGs, containing 1851 lncRNA-TF interactions and 6901 TF-promoter interactions. The lncRNA-to-target regulatory interactions were further validated by the triplex structures between the DElncRNAs and the promoters of the target DEGs. The DElncRNAs in the regulatory network were clustered into 3 clusters, one containing DElncRNAs correlated with the blood pressure, including FLNB-AS1 with targeting 27.89% (869/3116) DEGs in EOSPE. We further demonstrated that FLNB-AS1 could bind the transcription factor JUNB to regulate a series members of the HIF-1 signaling pathway in trophoblast cells. CONCLUSIONS: Our results suggest that the differential expression of lncRNAs may perturb the lncRNA-TF-DEG hierarchical regulatory network, leading to the dysregulation of many genes involved in EOSPE. Our study provides a new strategy and a valuable resource for studying the mechanism underlying gene dysregulation in EOSPE patients.
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Redes Reguladoras de Genes , Pré-Eclâmpsia , RNA Longo não Codificante , Pré-Eclâmpsia/genética , Humanos , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Feminino , Gravidez , Placenta/metabolismoRESUMO
The BEN domain-containing transcription factors regulate transcription by recruiting chromatin-modifying factors to specific chromatin regions via their DNA-binding BEN domains. The BEN domain of BANP has been shown to bind to a CGCG DNA sequence or an AAA-containing matrix attachment regions DNA sequence. Consistent with these in vivo observations, we identified an optimal DNA-binding sequence of AAATCTCG by protein binding microarray, which was also confirmed by our isothermal titration calorimetry and mutagenesis results. We then determined crystal structures of the BANP BEN domain in apo form and in complex with a CGCG-containing DNA, respectively, which revealed that the BANP BEN domain mainly used the electrostatic interactions to bind DNA with some base-specific interactions with the TC motifs. Our isothermal titration calorimetry results also showed that BANP bound to unmethylated and methylated DNAs with comparable binding affinities. Our complex structure of BANP-mCGCG revealed that the BANP BEN domain bound to the unmethylated and methylated DNAs in a similar mode and cytosine methylation did not get involved in binding, which is also consistent with our observations from the complex structures of the BEND6 BEN domain with the CGCG or CGmCG DNAs. Taken together, our results further elucidate the elements important for DNA recognition and transcriptional regulation by the BANP BEN domain-containing transcription factor.
Assuntos
Proteínas de Ligação a DNA , Regulação da Expressão Gênica , Fatores de Transcrição , Cromatina , DNA/química , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/química , Ligação Proteica , Fatores de Transcrição/genética , Fatores de Transcrição/química , HumanosRESUMO
Members of the E26 transformation-specific (ETS) variant transcription factor family act as either tumor suppressors or oncogenic factors in numerous types of cancer. ETS variant transcription factor 7 (ETV7) participates in the development of malignant tumors, whereas its involvement in colorectal cancer (CRC) is less clear. In this study, The Cancer Genome Atlas (TCGA) and immunochemistry staining were applied to check the clinical relevance of ETV7 and interferon-induced protein with tetratricopeptide repeats 3 (IFIT3) in CRC patients. Overexpression and knockdown of ETV7 and IFIT3 were conducted by transfecting the cells with pCDNA3.1 plasmids and siRNAs, respectively. Western blotting was used to detect the protein expression of ETV7 in CRC cells. Cell Counting Kit-8, cell colony formation, and Transwell assays, as well as flow cytometry, were used to evaluate the proliferation, migration, cell cycle, and apoptosis of CRC cells. Furthermore, western blotting, RT-qPCR, and luciferase assay were used to explore the regulation of ETV7 on IFIT3. Rescue assay was used to investigate the significance of ETV7/IFIT3 axis on CRC progression. We found that ETV7 was upregulated in CRC tissues and cells. Overexpression of ETV7 stimulated the proliferation, migration, and cell cycle amplification, and reduced the apoptosis of CRC cells. Downregulation of ETV7 exerted the opposite effect on CRC cell progression. Moreover, we demonstrated that ETV7 stimulated the transcription activity, the mRNA and protein expression of IFIT3 in CRC cells. There was a positive correlation between ETV7 and IFIT3 in CRC patients. IFIT3 knockdown reversed the promotive effect exerted by overexpression of ETV7 on the amplification and migration of CRC cells. By contrast, overexpression of IFIT3 blocked the inhibitory effect of ETV7-targeting siRNA. In summary, ETV7 induces progression of CRC by activating the transcriptional expression of IFIT3. The EVT7/IFIT3 axis may be a novel target for CRC therapy.
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Apoptose , Neoplasias Colorretais , Humanos , Regulação para Cima , Regulação para Baixo , Apoptose/genética , Neoplasias Colorretais/genética , Proteínas Proto-Oncogênicas c-ets , Peptídeos e Proteínas de Sinalização IntracelularRESUMO
Lithium dendrites belong to the key challenges of solid-state battery research. They are unavoidable due to the imperfect nature of surfaces containing defects of a critical size that can be filled by lithium until fracturing the solid electrolyte. The penetration of Li metal occurs along the propagating crack until a short circuit takes place. It is hypothesized that ion implantation can be used to introduce stress states into Li6.4La3Zr1.4Ta0.6O12 which enables an effective deflection and arrest of dendrites. The compositional and microstructural changes associated with the implantation of Ag-ions are studied via atom probe tomography, electron microscopy, and nano X-ray diffraction indicating that Ag-ions can be implanted up to 1 µm deep and amorphization takes place down to 650-700 nm, in good agreement with kinetic Monte Carlo simulations. Based on diffraction results pronounced stress states up to -700 MPa are generated in the near-surface region. Such a stress zone and the associated microstructural alterations exhibit the ability to not only deflect mechanically introduced cracks but also dendrites, as demonstrated by nano-indentation and galvanostatic cycling experiments with subsequent electron microscopy observations. These results demonstrate ion implantation as a viable technique to design "dendrite-free" solid-state electrolytes for high-power and energy-dense solid-state batteries.
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NF-Y transcription factors are known to play many diverse roles in the development and physiological responses of plants but little is known about their role in plant defense. Here, we demonstrate the negative roles of rice NF-YA family genes in antiviral defense against two different plant viruses, Rice stripe virus (RSV, Tenuivirus) and Southern rice black-streaked dwarf virus (SRBSDV, Fijivirus). RSV and SRBSDV both induced the expression of OsNF-YA family genes. Overexpression of OsNF-YAs enhanced rice susceptibility to virus infection, while OsNF-YAs RNAi mutants were more resistant. Transcriptome sequencing showed that the expression of jasmonic acid (JA)-related genes was significantly decreased in plants overexpressing OsNF-YA when they were infected by viruses. qRT-PCR and JA sensitivity assays confirmed that OsNF-YAs play negative roles in regulating the JA pathway. Further experiments showed that OsNF-YAs physically interact with JA signaling transcription factors OsMYC2/3 and interfere with JA signaling by dissociating the OsMYC2/3-OsMED25 complex, which inhibits the transcriptional activation activity of OsMYC2/3. Together, our results reveal that OsNF-YAs broadly inhibit plant antiviral defense by repressing JA signaling pathways, and provide new insight into how OsNF-YAs are directly associated with the JA pathway.
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Oryza , Tenuivirus , Viroses , Antivirais/metabolismo , Ciclopentanos , Regulação da Expressão Gênica de Plantas , Oryza/metabolismo , Oxilipinas , Doenças das Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Tenuivirus/genética , Tenuivirus/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Tryptophan (Trp) metabolism through the kynurenine pathway (KP) is well known to play a critical function in cancer, autoimmune and neurodegenerative diseases. However, its role in host-pathogen interactions has not been characterized yet. Herein, we identified that kynurenine-3-monooxygenase (KMO), a key rate-limiting enzyme in the KP, and quinolinic acid (QUIN), a key enzymatic product of KMO enzyme, exerted a novel antiviral function against a broad range of viruses. Mechanistically, QUIN induced the production of type I interferon (IFN-I) via activating the N-methyl-d-aspartate receptor (NMDAR) and Ca2+ influx to activate Calcium/calmodulin-dependent protein kinase II (CaMKII)/interferon regulatory factor 3 (IRF3). Importantly, QUIN treatment effectively inhibited viral infections and alleviated disease progression in mice. Furthermore, kmo-/- mice were vulnerable to pathogenic viral challenge with severe clinical symptoms. Collectively, our results demonstrated that KMO and its enzymatic product QUIN were potential therapeutics against emerging pathogenic viruses.
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Quinurenina 3-Mono-Oxigenase , Viroses , Animais , Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Fator Regulador 3 de Interferon/metabolismo , Cinurenina/metabolismo , Quinurenina 3-Mono-Oxigenase/metabolismo , Camundongos , Ácido Quinolínico/metabolismo , Ácido Quinolínico/farmacologia , Viroses/tratamento farmacológicoRESUMO
Deciduous woody plants like poplar (Populus spp.) have seasonal bud dormancy. It has been challenging to simultaneously delay the onset of bud dormancy in the fall and advance bud break in the spring, as bud dormancy, and bud break were thought to be controlled by different genetic factors. Here, we demonstrate that heterologous expression of the REVEILLE1 gene (named AaRVE1) from Agave (Agave americana) not only delays the onset of bud dormancy but also accelerates bud break in poplar in field trials. AaRVE1 heterologous expression increases poplar biomass yield by 166% in the greenhouse. Furthermore, we reveal that heterologous expression of AaRVE1 increases cytokinin contents, represses multiple dormancy-related genes, and up-regulates bud break-related genes, and that AaRVE1 functions as a transcriptional repressor and regulates the activity of the DORMANCY-ASSOCIATED PROTEIN 1 (DRM1) promoter. Our findings demonstrate that AaRVE1 appears to function as a regulator of bud dormancy and bud break, which has important implications for extending the growing season of deciduous trees in frost-free temperate and subtropical regions to increase crop yield.
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Agave , Populus , Proteínas de Plantas/metabolismo , Populus/metabolismo , Estações do Ano , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
In this paper, we propose a method for simultaneously recovering multiple radio wave signals based on nitrogen-vacancy (NV) centers in diamond combining optically detected magnetic resonance (ODMR) spectrum. A controlled magnetic field gradient applied to the laser excitation area on the surface of diamond widens the detectable ODMR bandwidth to 200â MHz. Three different frequency-modulated (FM) signals with distinct carrier frequencies falling within the resonance frequency range are received and demodulated in real-time. Subsequently, the FM signal reception capability of this system is further investigated by measuring baseband signal frequencies ranging from 0.1â Hz to 200â Hz and adjusting the carrier power within a dynamic range from -10 dBm to 30 dBm. This proposal, which accomplishes multi-channel demodulation using a compact and single device, has potential applications in fields such as wireless communication, radar and navigation.
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Cross-dehydrogenative couplings (CDC) present an efficient strategy for the assembly of biorelevant heterocycles, but are thus far largely limited to toxic transition metals and rather harsh reaction conditions. In sharp contrast, we, herein report on a mild photoelectrocatalyzed CDC-[4+2] annulation enabling the synthesis of functionalized isothiochromenes enabled by a proton-coupled electron transfer (PCET) strategy. The transformative photoelectrocatalysis obviated toxic transition-metal, high reaction temperatures, and stoichiometric chemical redox reagents. This approach was characterized by exceedingly mild conditions, ample substrate scope, and a commercially available catalyst. Gram-scale reactions and a telescoped synthesis route reflected the unique potential in the green synthesis of important S-heterocycles.
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Transmembrane protease, serine 2 (TMPRSS2) has been identified as key host cell factor for viral entry and pathogenesis of SARS-CoV-2. Specifically, TMPRSS2 proteolytically processes the SARS-CoV-2 Spike (S) protein, enabling virus-host membrane fusion and infection of the airways. We present here a recombinant production strategy for enzymatically active TMPRSS2 and characterization of its matured proteolytic activity, as well as its 1.95 Å X-ray cocrystal structure with the synthetic protease inhibitor nafamostat. Our study provides a structural basis for the potent but nonspecific inhibition by nafamostat and identifies distinguishing features of the TMPRSS2 substrate binding pocket that explain specificity. TMPRSS2 cleaved SARS-CoV-2 S protein at multiple sites, including the canonical S1/S2 cleavage site. We ranked the potency of clinical protease inhibitors with half-maximal inhibitory concentrations ranging from 1.4 nM to 120 µM and determined inhibitor mechanisms of action, providing the groundwork for drug development efforts to selectively inhibit TMPRSS2.
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COVID-19 , SARS-CoV-2 , Serina Endopeptidases/metabolismo , Humanos , Peptídeo Hidrolases , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Internalização do VírusRESUMO
The charge state of noble metal atoms on a semiconductor surface is an important factor in surface catalysis. In this study, Au atoms were deposited on the rutile TiO2(110) surface to characterize its charge properties using atomic force microscopy with Kelvin probe force microscopy at 78 K. Au single atoms, dimers, and trimers at different sites on the surface were investigated. Positively charged Au atoms were verified at oxygen sites, while negatively charged Au atoms were found near oxygen vacancy sites. Furthermore, the charge states of small Au nanoclusters were clarified. Understanding the charge states of Au atoms is significant for identifying their efficient catalytic effects in surface catalysis.