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The extracellular pH is a vital regulator of various biological processes in plants. However, how plants perceive extracellular pH remains obscure. Here, we report that plant cell-surface peptide-receptor complexes can function as extracellular pH sensors. We found that pattern-triggered immunity (PTI) dramatically alkalinizes the acidic extracellular pH in root apical meristem (RAM) region, which is essential for root meristem growth factor 1 (RGF1)-mediated RAM growth. The extracellular alkalinization progressively inhibits the acidic-dependent interaction between RGF1 and its receptors (RGFRs) through the pH sensor sulfotyrosine. Conversely, extracellular alkalinization promotes the alkaline-dependent binding of plant elicitor peptides (Peps) to its receptors (PEPRs) through the pH sensor Glu/Asp, thereby promoting immunity. A domain swap between RGFR and PEPR switches the pH dependency of RAM growth. Thus, our results reveal a mechanism of extracellular pH sensing by plant peptide-receptor complexes and provide insights into the extracellular pH-mediated regulation of growth and immunity in the RAM.
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Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Concentración de Iones de Hidrógeno , Meristema/metabolismo , Péptidos/metabolismo , Células Vegetales , Raíces de Plantas/metabolismo , Plantas/metabolismo , Receptores de Superficie Celular/metabolismo , Transducción de SeñalRESUMEN
Tumor-infiltrating myeloid cells (TIMs) are crucial cell populations involved in tumor immune escape, and their functions are regulated by multiple epigenetic mechanisms. The precise regulation mode of RNA N6-methyladenosine (m6A) modification in controlling TIM function is still poorly understood. Our study revealed that the increased expression of methyltransferase-like 3 (METTL3) in TIMs was correlated with the poor prognosis of colon cancer patients, and myeloid deficiency of METTL3 attenuated tumor growth in mice. METTL3 mediated m6A modification on Jak1 mRNA in TIMs, the m6A-YTHDF1 axis enhanced JAK1 protein translation efficiency and subsequent phosphorylation of STAT3. Lactate accumulated in tumor microenvironment potently induced METTL3 upregulation in TIMs via H3K18 lactylation. Interestingly, we identified two lactylation modification sites in the zinc-finger domain of METTL3, which was essential for METTL3 to capture target RNA. Our results emphasize the importance of lactylation-driven METTL3-mediated RNA m6A modification for promoting the immunosuppressive capacity of TIMs.
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Metiltransferasas , Neoplasias , Adenosina/metabolismo , Animales , Humanos , Terapia de Inmunosupresión , Metiltransferasas/genética , Metiltransferasas/metabolismo , Ratones , Células Mieloides/metabolismo , ARN , Microambiente TumoralRESUMEN
Although organic-inorganic hybrid materials have played indispensable roles as mechanical1-4, optical5,6, electronic7,8 and biomedical materials9-11, isolated organic-inorganic hybrid molecules (at present limited to covalent compounds12,13) are seldom used to prepare hybrid materials, owing to the distinct behaviours of organic covalent bonds14 and inorganic ionic bonds15 in molecular construction. Here we integrate typical covalent and ionic bonds within one molecule to create an organic-inorganic hybrid molecule, which can be used for bottom-up syntheses of hybrid materials. A combination of the organic covalent thioctic acid (TA) and the inorganic ionic calcium carbonate oligomer (CCO) through an acid-base reaction provides a TA-CCO hybrid molecule with the representative molecular formula TA2Ca(CaCO3)2. Its dual reactivity involving copolymerization of the organic TA segment and inorganic CCO segment generates the respective covalent and ionic networks. The two networks are interconnected through TA-CCO complexes to form a covalent-ionic bicontinuous structure within the resulting hybrid material, poly(TA-CCO), which unifies paradoxical mechanical properties. The reversible binding of Ca2+-CO32- bonds in the ionic network and S-S bonds in the covalent network ensures material reprocessability with plastic-like mouldability while preserving thermal stability. The coexistence of ceramic-like, rubber-like and plastic-like behaviours within poly(TA-CCO) goes beyond current classifications of materials to generate an 'elastic ceramic plastic'. The bottom-up creation of organic-inorganic hybrid molecules provides a feasible pathway for the molecular engineering of hybrid materials, thereby supplementing the classical methodology used for the manufacture of organic-inorganic hybrid materials.
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Flexible solar cells have a lot of market potential for application in photovoltaics integrated into buildings and wearable electronics because they are lightweight, shockproof and self-powered. Silicon solar cells have been successfully used in large power plants. However, despite the efforts made for more than 50 years, there has been no notable progress in the development of flexible silicon solar cells because of their rigidity1-4. Here we provide a strategy for fabricating large-scale, foldable silicon wafers and manufacturing flexible solar cells. A textured crystalline silicon wafer always starts to crack at the sharp channels between surface pyramids in the marginal region of the wafer. This fact enabled us to improve the flexibility of silicon wafers by blunting the pyramidal structure in the marginal regions. This edge-blunting technique enables commercial production of large-scale (>240 cm2), high-efficiency (>24%) silicon solar cells that can be rolled similarly to a sheet of paper. The cells retain 100% of their power conversion efficiency after 1,000 side-to-side bending cycles. After being assembled into large (>10,000 cm2) flexible modules, these cells retain 99.62% of their power after thermal cycling between -70 °C and 85 °C for 120 h. Furthermore, they retain 96.03% of their power after 20 min of exposure to air flow when attached to a soft gasbag, which models wind blowing during a violent storm.
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Microtubule (MT) minus ends are stabilized by CAMSAP family proteins at noncentrosomal MT-organizing centers. Despite progress in identifying diverse positive regulators, knowledge on the negative regulation of the MT minus-end distribution is lacking. Here, we identify CEP170B as a MT minus-end-binding protein that colocalizes with the microtubule-stabilizing complex at the cortical patches. CEP170B depends on the scaffold protein liprin-α1 for its cortical targeting and requires liprin-α1-bound PP2A phosphatase for its MT localization. CEP170B excludes CAMSAPs-stabilized MT minus ends from the cell periphery in HeLa cells and the basal cortex in human epithelial cells and is required for directional vesicle trafficking and cyst formation in 3D culture. Reconstitution experiments demonstrate that CEP170B autonomously tracks growing MT minus ends and blocks minus-end growth. Furthermore, CEP170B in a complex with the kinesin KIF2A acts as a potent MT minus-end depolymerase capable of antagonizing the stabilizing effect of CAMSAPs. Our study uncovers an antagonistic mechanism for controlling the spatial distribution of MT minus ends, which contributes to the establishment of polarized MT network and cell polarity.
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Proteínas Asociadas a Microtúbulos , Microtúbulos , Humanos , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Células HeLa , Microtúbulos/metabolismo , Proteínas del Citoesqueleto/metabolismo , Cinesinas/genética , Cinesinas/metabolismoRESUMEN
Protein O-glycosylation is a nutrient signaling mechanism that plays an essential role in maintaining cellular homeostasis across different species. In plants, SPINDLY (SPY) and SECRET AGENT (SEC) posttranslationally modify hundreds of intracellular proteins with O-fucose and O-linked N-acetylglucosamine, respectively. SPY and SEC play overlapping roles in cellular regulation, and loss of both SPY and SEC causes embryo lethality in Arabidopsis (Arabidopsis thaliana). Using structure-based virtual screening of chemical libraries followed by in vitro and in planta assays, we identified a SPY O-fucosyltransferase inhibitor (SOFTI). Computational analyses predicted that SOFTI binds to the GDP-fucose-binding pocket of SPY and competitively inhibits GDP-fucose binding. In vitro assays confirmed that SOFTI interacts with SPY and inhibits its O-fucosyltransferase activity. Docking analysis identified additional SOFTI analogs that showed stronger inhibitory activities. SOFTI treatment of Arabidopsis seedlings decreased protein O-fucosylation and elicited phenotypes similar to the spy mutants, including early seed germination, increased root hair density, and defective sugar-dependent growth. In contrast, SOFTI did not visibly affect the spy mutant. Similarly, SOFTI inhibited the sugar-dependent growth of tomato (Solanum lycopersicum) seedlings. These results demonstrate that SOFTI is a specific SPY O-fucosyltransferase inhibitor that can be used as a chemical tool for functional studies of O-fucosylation and potentially for agricultural management.
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Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas Represoras/metabolismo , Fucosiltransferasas/genética , Fucosiltransferasas/metabolismo , Fucosa/metabolismo , Plantones/metabolismo , Azúcares/metabolismoRESUMEN
Aromatic polyketides are renowned for their wide-ranging pharmaceutical activities. Their structural diversity is mainly produced via modification of limited types of basic frameworks. In this study, we characterized the biosynthesis of a unique basic aromatic framework, phenyldimethylanthrone (PDA) found in (+)/(-)-anthrabenzoxocinones (ABXs) and fasamycin (FAS). Its biosynthesis employs a methyltransferase (Abx(+)M/Abx(-)M/FasT) and an unusual TcmI-like aromatase/cyclase (ARO/CYC, Abx(+)D/Abx(-)D/FasL) as well as a nonessential helper ARO/CYC (Abx(+)C/Abx(-)C/FasD) to catalyze the aromatization/cyclization of polyketide chain, leading to the formation of all four aromatic rings of the PDA framework, including the C9 to C14 ring and a rare angular benzene ring. Biochemical and structural analysis of Abx(+)D reveals a unique loop region, giving rise to its distinct acyl carrier protein-dependent specificity compared to other conventional TcmI-type ARO/CYCs, all of which impose on free molecules. Mutagenic analysis discloses critical residues of Abx(+)D for its catalytic activity and indicates that the size and shape of its interior pocket determine the orientation of aromatization/cyclization. This study unveils the tetracyclic and non-TcmN type C9 to C14 ARO/CYC, significantly expanding our cognition of ARO/CYCs and the biosynthesis of aromatic polyketide framework.
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Aromatasa , Policétidos , Ciclización , Proteína Transportadora de Acilo , CatálisisRESUMEN
Extracellular matrix (ECM) rigidity serves as a crucial mechanical cue impacting diverse biological processes. However, understanding the molecular mechanisms of rigidity sensing has been limited by the spatial resolution and force sensitivity of current cellular force measurement techniques. Here we developed a method to functionalize DNA tension probes on soft hydrogel surfaces in a controllable and reliable manner, enabling molecular tension fluorescence microscopy for rigidity sensing studies. Our findings showed that fibroblasts respond to substrate rigidity by recruiting more force-bearing integrins and modulating integrin sampling frequency of the ECM, rather than simply overloading the existing integrin-ligand bonds, to promote focal adhesion maturation. We also demonstrated that ECM rigidity positively regulates the pN force of T cell receptor-ligand bond and T cell receptor mechanical sampling frequency, promoting T cell activation. Thus, hydrogel-based molecular tension fluorescence microscopy implemented on a standard confocal microscope provides a simple and effective means to explore detailed molecular force information for rigidity-dependent biological processes.
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Hidrogeles , Integrinas , Ligandos , Adhesiones Focales/química , Microscopía Fluorescente , Receptores de Antígenos de Linfocitos T , Adhesión CelularRESUMEN
Auxin inactivation is critical for plant growth and development. To develop plant growth regulators functioning in auxin inactivation pathway, we performed a phenotype-based chemical screen in Arabidopsis and identified a chemical, nalacin, that partially mimicked the effects of auxin. Genetic, pharmacological, and biochemical approaches demonstrated that nalacin exerts its auxin-like activities by inhibiting indole-3-acetic acid (IAA) conjugation that is mediated by Gretchen Hagen 3 (GH3) acyl acid amido synthetases. The crystal structure of Arabidopsis GH3.6 in complex with D4 (a derivative of nalacin) together with docking simulation analysis revealed the molecular basis of the inhibition of group II GH3 by nalacin. Sequence alignment analysis indicated broad bioactivities of nalacin and D4 as inhibitors of GH3s in vascular plants, which were confirmed, at least, in tomato and rice. In summary, our work identifies nalacin as a potent inhibitor of IAA conjugation mediated by group II GH3 that plays versatile roles in hormone-regulated plant development and has potential applications in both basic research and agriculture.
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Arabidopsis , Ligasas , Arabidopsis/genética , Ácidos Indolacéticos/farmacología , Fenómenos Químicos , Reguladores del Crecimiento de las Plantas/farmacología , Pruebas GenéticasRESUMEN
Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality globally. Many herbal medicines and their bioactive compounds have shown anti-tumor properties. This study was conducted to examine the effect of psilostachyin C (PSC), a sesquiterpenoid lactone isolated from Artemisia vulgaris L., in the malignant properties of HCC cells. CCK-8, flow cytometry, wound healing, and Transwell assays revealed that 25 µM PSC treatment significantly suppressed proliferation, cell cycle progression, migration, and invasion of two HCC cell lines (Hep 3B and Huh7) while promoting cell apoptosis. Bioinformatics prediction suggests CREB binding protein (CREBBP) as a promising target of PSC. CREBBP activated transcription of GATA zinc finger domain containing 2B (GATAD2B) by binding to its promoter. CREBBP and GATAD2B were highly expressed in clinical HCC tissues and the acquired HCC cell lines, but their expression was reduced by PSC. Either upregulation of CREBBP or GATAD2B restored the malignant properties of HCC cells blocked by PSC. Collectively, this evidence demonstrates that PSC pocessess anti-tumor functions in HCC cells by blocking CREBBP-mediated transcription of GATAD2B.
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Carcinoma Hepatocelular , Compuestos Heterocíclicos con 3 Anillos , Neoplasias Hepáticas , Pironas , Humanos , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Proteína de Unión a CREB/genética , Proteína de Unión a CREB/metabolismo , Línea Celular Tumoral , Proliferación Celular , Regulación Neoplásica de la Expresión GénicaRESUMEN
Mitochondrial DNA (mtDNA) is a unique genetic material characterized by maternal inheritance. It possesses a circular structure devoid of histone protection and exhibits low cellular abundance, which poses great challenges for its sensitive and selective detection at the living cell level. Herein, we have designed three bis-naphthylimide probes with varying linker lengths (NANn-OH, n = 0, 2, 6), facilitating the formation of distinct twisted or folded molecular conformations in the free state. These probes emit the red fluorescence around 627 nm with different fluorescence quantum yields (ΦNAN0-OH = 0.0016, ΦNAN2-OH = 0.0136, and ΦNAN6-OH = 0.0125). When encountering mtDNA (0.4-3.4 µg/mL), these probes undergo conformational changes depending on the length of the attached C-strand and exhibit a gradually increasing fluorescence signal around 453 nm. The fluorescence intensity increased to 13.5-fold, 1.9-fold, and 8.2-fold, respectively. Notably, the red fluorescence intensities around 627 nm remain constant throughout this process, thus serving as an inherent correction mechanism for proportional fluorescence signal enhancement to improve selectivity and sensitivity. NAN0-OH, NAN2-OH, and NAN6-OH showed good linearity for mtDNA in the range of 0.4-3.4 µg/mL with detection limits of LODNAN0-OH = 1.04 µg/mL, LODNAN2-OH = 1.10 µg/mL, and LODNAN6-OH = 1.15 µg/mL. Cellular experiments reveal that NAN6-OH effectively monitors curcumin-induced mtDNA damage in HepG-2 cells while enabling monitoring of genetic mtDNA damage. We anticipate that this tool holds significant potential for the precise evaluation of maternal genetic defects, thereby enhancing hypersensitive assessment in clinical medicine.
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The two-dimensional (2D) monolayer material MoSi2N4 was successfully synthesized in 2020[Hong et al., Science 369, 670, (2020)], exhibiting a plethora of new phenomena and unusual properties, with good stability at room temperature. However, MA2Z4 family monolayer materials involve primarily transition metal substitutions for M atoms. In order to address the research gap on lanthanide and actinide MA2Z4 materials, this work conducts electronic structure calculations on novel 2D MSi2N4 (M = La, Eu) monolayer materials by employing first-principles methods and CASTEP. High carrier mobility is discovered in the indirect bandgap semiconductor 2D LaSi2N4 monolayer (~5400 cm2 V-1 s-1) and in the spin (spin-down channel) carrier mobility of the half-metallic ferromagnetic EuSi2N4 monolayer (~2800 cm2 V-1 s-1). EuSi2N4 monolayer supplements research on spin carrier mobility in half-metallic ferromagnetic monolayer materials at room temperature and possesses a magnetic moment of 5 µB, which should not be underestimated. Furthermore, due to the unique electronic band structure of EuSi2N4 monolayer (with the spin-up channel exhibiting metallic properties and the spin-down channel exhibiting semiconductor properties), it demonstrates a 100% spin polarization rate, presenting significant potential applications in fields such as magnetic storage, magnetic sensing, and spintronics.
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A series of pentagonal bipyramidal anionic germanium clusters doped with heavy rare earth elements, REGe 6 - (RE = Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu), have been identified at the PBE0/def2-TZVP level using density functional theory (DFT). Our findings reveal that the centrally doped pentagonal ring structure demonstrates enhanced stability and heightened aromaticity due to its uniform bonding characteristics and a larger charge transfer region. Through natural population analysis and spin density diagrams, we observed a monotonic decrease in the magnetic moment from Gd to Yb. This is attributed to the decreasing number of unpaired electrons in the 4f orbitals of the heavy rare earth atoms. Interestingly, the system doped with Er atoms showed lower stability and anti-aromaticity, likely due to the involvement of the 4f orbitals in bonding. Conversely, the systems doped with Gd and Tb atoms stood out for their high magnetism and stability, making them potential building blocks for rare earth-doped semiconductor materials.
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Wearable soft contact lens sensors for continuous and nondestructive intraocular pressure (IOP) monitoring are highly desired as glaucoma and postoperative myopia patients grow, especially as the eyestrain crowd increases. Herein, a smart closed-loop system is presented that combines a Ti3C2Tx MXene-based soft contact lens (MX-CLS) sensor, wireless data transmission units, display, and warning components to realize continuous and nondestructive IOP monitoring/real-time display. The fabricated MX-CLS device exhibits an extremely high sensitivity of 7.483 mV mmHg-1, good linearity on silicone eyeballs, excellent stability under long-term pressure-release measurement, sufficient transparency with 67.8% transmittance under visible illumination, and superior biocompatibility with no discomfort when putting the MX-CLS sensor onto the Rabbit eyes. After integrating with the wireless module, users can realize real-time monitoring and warning of IOP via smartphones, the demonstrated MX-CLS device together with the IOP monitoring/display system opens up promising platforms for Ti3C2Tx materials as the base for multifunctional contact lens-based sensors and continuous and nondestructive IOP measurement system.
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Lentes de Contacto Hidrofílicos , Presión Intraocular , Titanio , Presión Intraocular/fisiología , Animales , Conejos , Titanio/química , Monitoreo Fisiológico/métodos , Monitoreo Fisiológico/instrumentaciónRESUMEN
Solid-state batteries (SSBs) are under development as high-priority technologies for safe and energy-dense next-generation electrochemical energy storage systems operating over a wide temperature range. Solid-state electrolytes (SSEs) exhibit high thermal stability and, in some cases, the ability to prevent dendrite growth through a physical barrier, and compatibility with the "holy grail" metallic lithium. These unique advantages of SSEs have spurred significant research interests during the last decade. Garnet-type SSEs, that is, Li7La3Zr2O12 (LLZO), are intensively investigated due to their high Li-ion conductivity and exceptional chemical and electrochemical stability against lithium metal anodes. However, poor interfacial contact with cathode materials, undesirable lithium plating along grain boundaries, and moisture-induced chemical degradation greatly hinder the practical implementation of LLZO-based SSEs for SSBs. In this review, the recent advances in synthesis methods, modification strategies, corresponding mechanisms, and applications of garnet-based SSEs in SSBs are critically summarized. Furthermore, a comprehensive evaluation of the challenges and development trends of LLZO-based electrolytes in practical applications is presented to accelerate their development for high-performance SSBs.
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Noble metal single-atom-catalysts (SACs) have demonstrated significant potential to improve atom utilization efficiency and catalytic activity for hydrogen evolution reaction (HER). However, challenges still remain in rationally modulating active sites and catalytic activities of SACs, which often results in sluggish kinetics and poor stability, especially in neutral/alkaline media. Herein, precise construction of Pt single atoms anchored on edge of 2D layered Ni(OH)2 (Pt-Ni(OH)2-E) is achieved utilizing in situ electrodeposition. Compared to the single-atom Pt catalysts anchored on the basal plane of Ni(OH)2 (Pt-Ni(OH)2-BP), the Pt-Ni(OH)2-E possesses superior electron affinity and high intrinsic catalytic activity, which favors the strong adsorption and rapid dissociation toward water molecules. As a result, the Pt-Ni(OH)2-E catalyst requires low overpotentials of 21 and 34 mV at 10 mA cm-2 in alkaline and neutral conditions, respectively. Specifically, it shows the high mass activity of 23.6 A mg-1 for Pt at the overpotential of 100 mV, outperforming the reported catalysts and commercial Pt/C. This work provides new insights into the rational design of active sites for preparing high-performance SACs.
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Constructing a flexible and chemically stable multifunctional layer for the lithium (Li) metal anodes is a highly effective approach to improve the uneven deposition of Li+ and suppress the dendrite growth. Herein, an organic protecting layer of polythiophene is in situ polymerized on the Li metal via plasma polymerization. Compared with the chemically polymerized thiophene (C-PTh), the plasma polymerized thiophene layer (P-PTh), with a higher Young's modulus of 8.1 GPa, shows strong structural stability due to the chemical binding of the polythiophene and Li. Moreover, the nucleophilic CâS bond of polythiophene facilitates the decomposition of Li salts in the electrolytes, promoting the formation of LiF-rich solid electrolyte interface (SEI) layers. The synergetic effect of the rigid LiF as well as the flexible PTh-Li can effectively regulate the uniform Li deposition and suppress the growth of Li dendrites during the repeated stripping-plating, enabling the Li anodes with long-cycling lifespan over 8000 h (1 mA cm-2, 1 mAh cm-2) and 2500 h (10 mA cm-2, 10 mAh cm-2). Since the plasma polymerization is facile (5-20 min) and environmentally friendly (solvent-free), this work offers a novel and promising strategy for the construction of the forthcoming generation of high-energy-density batteries.
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Scoring functions are important components in molecular docking for structure-based drug discovery. Traditional scoring functions, generally empirical- or force field-based, are robust and have proven to be useful for identifying hits and lead optimizations. Although multiple highly accurate deep learning- or machine learning-based scoring functions have been developed, their direct applications for docking and screening are limited. We describe a novel strategy to develop a reliable protein-ligand scoring function by augmenting the traditional scoring function Vina score using a correction term (OnionNet-SFCT). The correction term is developed based on an AdaBoost random forest model, utilizing multiple layers of contacts formed between protein residues and ligand atoms. In addition to the Vina score, the model considerably enhances the AutoDock Vina prediction abilities for docking and screening tasks based on different benchmarks (such as cross-docking dataset, CASF-2016, DUD-E and DUD-AD). Furthermore, our model could be combined with multiple docking applications to increase pose selection accuracies and screening abilities, indicating its wide usage for structure-based drug discoveries. Furthermore, in a reverse practice, the combined scoring strategy successfully identified multiple known receptors of a plant hormone. To summarize, the results show that the combination of data-driven model (OnionNet-SFCT) and empirical scoring function (Vina score) is a good scoring strategy that could be useful for structure-based drug discoveries and potentially target fishing in future.
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Descubrimiento de Drogas , Proteínas , Descubrimiento de Drogas/métodos , Ligandos , Aprendizaje Automático , Simulación del Acoplamiento Molecular , Unión Proteica , Proteínas/químicaRESUMEN
The aggravation of energy problems and the scarcity of lithium resources have forced us to look for new energy storage systems. Aluminum ion batteries, as a promising energy storage system, have the advantages of environmental friendliness and abundant aluminum resources, and have the potential for application in large-scale energy storage and personal portable electronic devices. To solve the stability problem of aluminum ion batteries during cycling for large-scale energy storage needs, we report a polythiophene-based conductive polymer, poly(3,4-dimethylthiophene) (PDMT), as a high performance cathode material for aluminum ion batteries. By introducing two methyl groups on the thiophene ring, we successfully adjust the local charge density of the heterocyclic thiophene, thus changing the electron delocalization characteristics, and improving the electrochemical reaction activity of the polythiophene (PTH) material as a redox electrode material. This also maintains the symmetry and regularity of the polymer structure, giving the material better cycling stability. The discharge specific capacity reaches 110â mAh g-1 at a current density of 200â mA g-1, far exceeding conventional PTH cathodes (~70â mAh g-1), and the capacity retention rate is 92.7 % after 1000 cycles. It also shows excellent rate performance due to the flexible structure of the conductive polymer.
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The effective regeneration of large bone defects via bone tissue engineering is challenging due to the difficulty in creating an osteogenic microenvironment. Inspired by the fibrillar architecture of the natural extracellular matrix, we developed a nanoscale bioengineering strategy to produce bone fibril-like composite scaffolds with enhanced osteogenic capability. To activate the surface for biofunctionalization, self-adaptive ridge-like nanolamellae were constructed on poly(ε-caprolactone) (PCL) electrospinning scaffolds via surface-directed epitaxial crystallization. This unique nanotopography with a markedly increased specific surface area offered abundant nucleation sites for Ca2+ recruitment, leading to a 5-fold greater deposition weight of hydroxyapatite than that of the pristine PCL scaffold under stimulated physiological conditions. Bone marrow mesenchymal stem cells (BMSCs) cultured on bone fibril-like scaffolds exhibited enhanced adhesion, proliferation, and osteogenic differentiation in vitro. In a rat calvarial defect model, the bone fibril-like scaffold significantly accelerated bone regeneration, as evidenced by micro-CT, histological histological and immunofluorescence staining. This work provides the way for recapitulating the osteogenic microenvironment in tissue-engineered scaffolds for bone repair.