Damage Evolution and Acoustic Emission Characteristics of Sandstone under Freeze-Thaw Cycles.

The deformation and fracture characteristics of rocks under freeze-thaw cycles were investigated by using uniaxial compression tests with acoustic emission (AE) monitoring. The results showed that the sandstone peak stress and elastic modulus decreased with an increasing number of freeze-thaw cycles, and the strain increased significantly. The rates of increase in the total energy and elastic energy decreased with an increasing number of freeze-thaw cycles. The freeze-thaw damage factor De was directly proportional to the number of freeze-thaw cycles. The total damage factor D was inversely proportional to the freeze-thaw cycles when the freeze-thaw-induced damage and load-induced damage were coupled. By analyzing the AE energy rate, event rate, amplitude, and frequency of the sandstone during damage, it was found that the amplitude varies irregularly with the freeze-thaw cycles and that the AE energy and event rates can better show the development of internal cracks in the sandstone. The peak frequency was the most sensitive and could be used as an index to predict when the sandstone ultimately failed. The increase in the number of freeze-thaw cycles encouraged the development of internal cracks in the sandstone. The crack characteristics change from mixed tensile-shear fractures before they undergo freeze-thaw cycles to tensile fracturing after a high number of freeze-thaw cycles. These research results provide a valuable reference for understanding the mechanisms of rock damage caused by freeze-thaw cycles as well as for making predictions about the safety of engineering structures in cold climates.

Biochar application for the remediation of soil contaminated with potentially toxic elements: Current situation and challenges.

Recently, biochar has garnered extensive attention in the remediation of soils contaminated with potentially toxic elements (PTEs) owing to its exceptional adsorption properties and straightforward operation. Most researchers have primarily concentrated on the effects, mechanisms, impact factors, and risks of biochar in remediation of PTEs. However, concerns about the long-term safety and impact of biochar have restricted its application. This review aims to establish a basis for the large-scale popularization of biochar for remediating PTEs-contaminated soil based on a review of interactive mechanisms between soil, PTEs and biochar, as well as the current situation of biochar for remediation in PTEs scenarios. Biochar can directly interact with PTEs or indirectly with soil components, influencing the bioavailability, mobility, and toxicity of PTEs. The efficacy of biochar in remediation varies depending on biomass feedstock, pyrolysis temperature, type of PTEs, and application rate. Compared to pristine biochar, modified biochar offers feasible solutions for tailoring specialized biochar suited to specific PTEs-contaminated soil. Main challenges limiting the applications of biochar are overdose and potential risks. The used biochar is separated from the soil that not only actually removes PTEs, but also mitigates the negative long-term effects of biochar. A sustainable remediation technology is advocated that enables the recovery and regeneration (95.0-95.6%) of biochar from the soil and the removal of PTEs (the removal rate of Cd is more than 20%) from the soil. Finally, future research directions are suggested to augment the environmental safety of biochar and promote its wider application.

Geographical distribution-based differentiation of cultivated Angelica dahurica, exploring the relationship between the secretory tract and the quality.

Based on geographical distribution, cultivated Chinese Angelica dahurica has been divided into Angelica dahurica cv. 'Hangbaizhi' (HBZ) and Angelica dahurica cv. 'Qibaizhi' (QBZ). Long-term geographical isolation has led to significant quality differences between them. The secretory structure in medicinal plants, as a place for accumulating effective constituents and information transmission to the environment, links the environment with the quality of medicinal materials. However, the secretory tract differences between HBZ and QBZ has not been revealed. This study aimed to explore the relationship between the secretory tract and the quality of two kinds of A. dahurica. Root samples were collected at seven development phases. High-Performance Liquid Chromatography (HPLC) and Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI-MSI) were used for the content determination and spatial location of coumarins. Paraffin section was used to observe and localize the root secretory tract. Origin, CaseViewer, and HDI software were used for data analysis and image processing. The results showed that compared to QBZ, HBZ, with better quality, has a larger area of root secretory tracts. Hence, the root secretory tract can be included in the quality evaluation indicators of A. dahurica. Additionally, DESI-MSI technology was used for the first time to elucidate the temporal and spatial distribution of coumarin components in A. dahurica root tissues. This study provides a theoretical basis for the quality evaluation and breeding of improved varieties of A. dahurica and references the DESI-MSI technology used to analyze the metabolic differences of various compounds, including coumarin and volatile oil, in different tissue parts of A. dahurica.

Discovery of 2-Aminothiazole-4-carboxylic Acids as Broad-Spectrum Metallo-ß-lactamase Inhibitors by Mimicking Carbapenem Hydrolysate Binding.

Metallo-ß-lactamases (MBLs) are zinc-dependent enzymes capable of hydrolyzing all bicyclic ß-lactam antibiotics, posing a great threat to public health. However, there are currently no clinically approved MBL inhibitors. Despite variations in their active sites, MBLs share a common catalytic mechanism with carbapenems, forming similar reaction species and hydrolysates. We here report the development of 2-aminothiazole-4-carboxylic acids (AtCs) as broad-spectrum MBL inhibitors by mimicking the anchor pharmacophore features of carbapenem hydrolysate binding. Several AtCs manifested potent activity against B1, B2, and B3 MBLs. Crystallographic analyses revealed a common binding mode of AtCs with B1, B2, and B3 MBLs, resembling binding observed in the MBL-carbapenem product complexes. AtCs restored Meropenem activity against MBL-producing isolates. In the murine sepsis model, AtCs exhibited favorable synergistic efficacy with Meropenem, along with acceptable pharmacokinetics and safety profiles. This work offers promising lead compounds and a structural basis for the development of potential drug candidates to combat MBL-mediated antimicrobial resistance.

Elderly Fall Detection Based on GCN-LSTM Multi-Task Learning Using Nursing Aids Integrated with Multi-Array Flexible Tactile Sensors.

Due to the frailty of elderly individuals' physical condition, falling can lead to severe bodily injuries. Effective fall detection can significantly reduce the occurrence of such incidents. However, current fall detection methods heavily rely on visual and multi-sensor devices, which incur higher costs and complex wearable designs, limiting their wide-ranging applicability. In this paper, we propose a fall detection method based on nursing aids integrated with multi-array flexible tactile sensors. We design a kind of multi-array capacitive tactile sensor and arrange the distribution of tactile sensors on the foot based on plantar force analysis and measure tactile sequences from the sole of the foot to develop a dataset. Then we construct a fall detection model based on a graph convolution neural network and long-short term memory network (GCN-LSTM), where the GCN module and LSTM module separately extract spatial and temporal features from the tactile sequences, achieving detection on tactile data of foot and walking states for specific time series in the future. Experiments are carried out with the fall detection model, the Mean Squared Error (MSE) of the predicted tactile data of the foot at the next time step is 0.0716, with the fall detection accuracy of 96.36%. What is more, the model can achieve fall detection on 5-time steps with 0.2-s intervals in the future with high confidence results. It exhibits outstanding performance, surpassing other baseline algorithms. Besides, we conduct experiments on different ground types and ground morphologies for fall detection, and the model showcases robust generalization capabilities.

Light-mediated anthocyanin biosynthesis in rose petals involves a balanced regulatory module comprising transcription factors RhHY5, RhMYB114a, and RhMYB3b.

Roses are significant botanical species with both ornamental and economic value, displaying diverse floral traits, particularly an extensive array of petal colors. The red pigmentation of rose petals is predominantly attributed to anthocyanin accumulation. However, the underlying regulatory mechanism of anthocyanin biosynthesis in roses remains elusive. This study presents a novel light-responsive regulatory module governing anthocyanin biosynthesis in rose petals, which involves the transcription factors RhHY5, RhMYB114a, and RhMYB3b. Under light conditions (1000-1500 µmol m-2 s-1), RhHY5 represses RhMYB3b expression and induces RhMYB114a expression, positively regulating anthocyanin biosynthesis in rose petals. Notably, activation of anthocyanin structural genes probably involves an interaction and synergy between RhHY5 and the MYB114a-bHLH3-WD40 complex. Additionally, RhMYB3b is activated by RhMYB114a to prevent excessive accumulation of anthocyanin. Conversely, under low light conditions (<10 µmol m-2 s-1), the degradation of RhHY5 leads to down-regulation of RhMYB114a and up-regulation of RhMYB3b, which in turn inhibits the expression of both RhMYB114a and anthocyanin structural genes. Additionally, RhMYB3b competes with RhMYB114a for binding to RhbHLH3 and the promoters of anthocyanin-related structural genes. Overall, our study uncovers a complex light-mediated regulatory network that governs anthocyanin biosynthesis in rose petals, providing new insights into the molecular mechanisms underlying petal color formation in rose.

Metal binding pharmacophore click-derived discovery of new broad-spectrum metallo-ß-lactamase inhibitors.

The emergence of metallo-ß-lactamases (MBLs) confers resistance to nearly all the ß-lactam antibiotics, including carbapenems. Currently, there is a lack of clinically useful MBL inhibitors, making it crucial to discover new inhibitor chemotypes that can potently target multiple clinically relevant MBLs. Herein we report a strategy that utilizes a metal binding pharmacophore (MBP) click approach to identify new broad-spectrum MBL inhibitors. Our initial investigation identified several MBPs including phthalic acid, phenylboronic acid and benzyl phosphoric acid, which were subjected to structural transformations using azide-alkyne click reactions. Subsequent structure-activity relationship analyses led to the identification of several potent broad-spectrum MBL inhibitors, including 73 that manifested IC50 values ranging from 0.00012 µM to 0.64 µM against multiple MBLs. Co-crystallographic studies demonstrated the importance of MBPs in engaging with the MBL active site anchor pharmacophore features, and revealed the unusual two-molecule binding modes with IMP-1, highlighting the critical role of flexible active site loops in recognizing structurally diverse substrates/inhibitors. Our work provides new chemotypes for MBL inhibition and establishes a MBP click-derived paradigm for inhibitor discovery targeting MBLs as well as other metalloenzymes.

Metallo-ß-lactamase-mediated antimicrobial resistance and progress in inhibitor discovery.

Resistance to ß-lactam antibiotics is rapidly growing, substantially due to the spread of serine-ß-lactamases (SBLs) and metallo-ß-lactamases (MBLs), which efficiently catalyse ß-lactam hydrolysis. Combinations of a ß-lactam antibiotic with an SBL inhibitor have been clinically successful; however, no MBL inhibitors have been developed for clinical use. MBLs are a worrying resistance vector because they catalyse hydrolysis of all ß-lactam antibiotic classes, except the monobactams, and they are being disseminated across many bacterial species worldwide. Here we review the classification, structures, substrate profiles, and inhibition mechanisms of MBLs, highlighting current clinical problems due to MBL-mediated resistance and progress in understanding and combating MBL-mediated resistance.

New ε-N-thioglutaryl-lysine derivatives as SIRT5 inhibitors: Chemical synthesis, kinetic and crystallographic studies.

SIRT5 has been implicated in various physiological processes and human diseases, including cancer. Development of new highly potent, selective SIRT5 inhibitors is still needed to investigate disease-related mechanisms and therapeutic potentials. We here report new ε-N-thioglutaryllysine derivatives, which were designed according to SIRT5-catalysed deacylation reactions. These ε-N-thioglutaryllysine derivatives displayed potent SIRT5 inhibition, of which the potential photo-crosslinking derivative 8 manifested most potent inhibition with an IC50 value of 120 nM to SIRT5, and low inhibition to SIRT1-3 and SIRT6. The enzyme kinetic assays revealed that the ε-N-thioglutaryllysine derivatives inhibit SIRT5 by lysine-substrate competitive manner. Co-crystallographic analyses demonstrated that 8 binds to occupy the lysine-substate binding site by making hydrogen-bonding and electrostatic interactions with SIRT5-specific residues, and is likely positioned to react with NAD+ and form stable thio-intermediates. Compound 8 was observed to have low photo-crosslinking probability to SIRT5, possibly due to inappropriate position of the diazirine group as observed in SIRT5:8 crystal structure. This study provides useful information for developing drug-like inhibitors and cross-linking chemical probes for SIRT5-related studies.

Bioinformatics analysis of the clinical significance of HLA class II in breast cancer.

Human leukocyte antigen (HLA) class II plays critical roles in antigen presentation and the initiation of immune responses. However, the correlation between the HLA class II gene expression level and the survival of patients with breast cancer is still under investigation. We analyzed microarray and RNA-Seq data of breast cancer from the cancer genome atlas (TCGA), genotype-tissue expression (GTEx) and Oncomine databases by using bioinformatics tools. The expression of the HLA-DQA1, HLA-DQA2, and HLA-DQB2 genes was significantly upregulated in breast cancer. Higher expression levels of HLA class II genes in breast cancer, especially HLA-DOB and HLA-DQB2, were significantly associated with better overall survival. Furthermore, the expression of HLA class II genes was more closely associated with survival in breast cancer than in other cancer types. CD48 coexpressed with both HLA-DOB and HLA-DQB2 was also positively associated with the overall survival of breast cancer patients. The results indicated that HLA class II and CD48 may enhance antitumor immunity, and their expression patterns may serve as potential prognostic biomarkers and therapeutic targets in breast cancer.

Design, Synthesis, and Biological Evaluation of New 1H-Imidazole-2-Carboxylic Acid Derivatives as Metallo-ß-Lactamase Inhibitors.

As one of important mechanisms to ß-lactam antimicrobial resistance, metallo-ß-lactamases (MBLs) have been receiving increasing worldwide attentions. Ambler subclass B1 MBLs are most clinically relevant, because they can hydrolyze almost all ß-lactams with the exception of monobactams. However, it is still lacking of clinically useful drugs to combat MBL-medicated resistance. We previously identified 1H-imidazole-2-carboxylic acid as a core metal-binding pharmacophore (MBP) to target multiple B1 MBLs. Herein, we report structural optimization of 1H-imidazole-2-carboxylic acid and substituents. Structure-activity relationship (SAR) analyses revealed that replacement of 1H-imidazole-2-carboxylic acid with other structurally highly similar MBPs excepting thiazole-4-carboxylic acid resulted in decreased MBL inhibition. Further SAR studies identified more potent inhibitors to MBLs, of which 28 manifested IC50 values of 0.018 µM for both VIM-2 and VIM-5. The microbiological tests demonstrated that the most tested compounds showed improved synergistic effects; some compounds at 1 µg/ml were able to reduce meropenem MIC by at least 16-fold, which will be worth further development of new potent inhibitors particularly targeting VIM-type MBLs.

Study on the potential mechanism, therapeutic drugs and prescriptions of insomnia based on bioinformatics and molecular docking.

Insomnia is a very common disease worldwide. It seriously affects the quality of human life and even endangers health. Traditional Chinese medicine (TCM) has unique advantages in the intervention and treatment of insomnia. However, its underlying mechanism has yet to be elucidated. This study was performed to explore the potential biomarkers and mechanisms of insomnia, and treatment TCM and classical prescriptions. The gene microarray data of insomnia is downloaded and preprocessed. Differentially expressed genes (DEGs) and GO and KEGG enrichment analyses were performed. The protein-protein interaction network (PPI) was constructed. Small molecule drugs for curing insomnia were identified using cMap and CTD databases. We searched the TCM corresponding to small molecule drugs and the classic prescriptions corresponding to TCM by the TCMSP database. We constructed a network of "ingredient-TCM-classic prescriptions". The molecular docking was performed to validate the screening results. We obtained a total of 124 DEGs, including 78 up-regulated genes, 46 down-regulated genes, 10 Hub genes and 3 key modules. A total of 125 significant GO entries and 15 significant KEGG were enriched (P < 0.05). The main biological processes involve neuronal apoptosis, autophagy, cell growth and apoptosis, etc. These signaling pathways may be involved in molecular regulatory mechanisms of insomnia, such as autophagy regulation, Alzheimer's disease, pathways to neurodegenerative diseases and neurotrophic factor signaling pathways. We identified 10 traditional Chinese medicines and 2 classical prescriptions of potential value. In addition, the molecular docking results indicated that small molecule ligands were nicely bound to the Hub gene, and the binding affinity ranged from -7.6 to -9.7 kcal/mol. This study provides a foundation for the clinical treatment of insomnia, explains the molecular mechanisms, and efficiently develops TCM and classical prescriptions.

Dynamic Variation of Amino Acid Contents and Identification of Sterols in Xinyang Mao Jian Green Tea.

As important biomolecules in Camellia sinensis L., amino acids (AAs) are considered to contribute to the overall green tea sensory quality and undergo dynamic changes during growth. However, limited by analytical capacity, detailed AAs composition in different growth stages remains unclear. To address this question, we analyzed the dynamic changes of 23 AAs during leaf growth in Xinyang Mao Jian (XYMJ) green tea. Using amino acid analyzer, we demonstrated that most AAs are abundant on Pure Brightness Day and Grain Rain Day. After Grain Rain, 23 AAs decreased significantly. Further analysis shows that theanine has a high level on the day before Spring Equinox and Grain Rain, accounting for 44-61% of the total free AAs content in tea leaves. Glu, Pro, and Asp are the second most abundant AAs. Additionally, spinasterol and 22,23-dihydrospinasterol are first purified and identified in ethanol extract of XYMJ by silica gel column chromatography method. This study reveals the relationship between plucking days and the dynamic changes of AAs during the growth stage and proves the rationality of the traditional plucking days of XYMJ green tea.

Tissue-Specific Expression of the Terpene Synthase Family Genes in Rosa chinensis and Effect of Abiotic Stress Conditions.

Rose (Rosa chinensis) is one of the most famous ornamental plants worldwide, with a variety of colors and fragrances. Terpene synthases (TPSs) play critical roles in the biosynthesis of terpenes. In this work, we report a comprehensive study on the genome-wide identification and characterization of the TPS family in R. chinensis. We identified 49 TPS genes in the R. chinensis genome, and they were grouped into five subfamilies (TPS-a, TPS-b, TPS-c, TPS-g and TPS-e/f). Phylogenetics, gene structure and conserved motif analyses indicated that the RcTPS genes possessed relatively conserved gene structures and the RcTPS proteins contained relatively conserved motifs. Multiple putative cis-acting elements involved in the stress response were identified in the promoter region of RcTPS genes, suggesting that some could be regulated by stress. The expression profile of RcTPS genes showed that they were predominantly expressed in the petals of open flowers, pistils, leaves and roots. Under osmotic and heat stresses, the expression of most RcTPS genes was upregulated. These data provide a useful foundation for deciphering the functional roles of RcTPS genes during plant growth as well as addressing the link between terpene biosynthesis and abiotic stress responses in roses.

[Composition changes reveal relationship between color and enzymatic reaction of Magnoliae Officinalis Cortex during "sweating" process].

In this study, we employed Q Exactive to determine the main differential metabolites of Magnoliae Officinalis Cortex du-ring the "sweating" process. Further, we quantified the color parameters and determined the activities of polyphenol oxidase(PPO), peroxidase(POD), and tyrosinase of Magnoliae Officinalis Cortex during the "sweating" process. Gray correlation analysis was performed for the color, chemical composition, and enzyme activity to reveal the effect of enzymatic reaction on the color of Magnoliae Officinalis Cortex during the "sweating" process. Magnoliae Officinalis Cortex sweating in different manners showed similar metabolite changes. The primary metabolites that changed significantly included amino acids, nucleotides, and sugars, and the secondary metabolites with significant changes were phenols and phenylpropanoids. Despite the different sweating methods, eleven compounds were commonly up-regulated, including L-glutamic acid, acetylarginine, hypoxanthine, and xanthine; six compounds were commonly down-re-gulated, including L-arginine, L-aspartic acid, and phenylalanine. The brightness value(L~*), red-green value(a~*), and yellow-blue value(b~*) of Magnoliae Officinalis Cortex kept decreasing during the "sweating" process. The changes in the activities of PPO and POD during sweating were consistent with those in the color parameter values. The gray correlation analysis demonstrated that the main differential metabolites such as amino acids and phenols were closely related to the color parameters L~*, a~* and b~*; POD was correlated with amino acids and phenols; PPO had strong correlation with phenols. The results indicated that the color change of Magnoliae Officinalis Cortex during "sweating" was closely related to the reactions of enzymes dominated by PPO and POD. The study analyzed the correlations among the main differential metabolites, color parameters, and enzyme activities of Magnoliae Officinalis Cortex in the "sweating" process. It reveals the common law of material changes and ascertains the relationship between color changes and enzymatic reactions of Magnoliae Officinalis Cortex during "sweating". Therefore, this study provides a reference for studying the "sweating" mechanism of Magnoliae Officinalis Cortex and is of great significance to guarantee the quality of Magnoliae Officinalis Cortex.

Structure-guided optimization of 1H-imidazole-2-carboxylic acid derivatives affording potent VIM-Type metallo-ß-lactamase inhibitors.

Production of metallo-ß-lactamases (MBLs) in bacterial pathogens is an important cause of resistance to the 'last-resort' carbapenem antibiotics. Development of effective MBL inhibitors to reverse carbapenem resistance in Gram-negative bacteria is still needed. We herein report X-ray structure-guided optimization of 1H-imidazole-2-carboxylic acid (ICA) derivatives by considering how to engage with the active-site flexible loops and improve penetration into Gram-negative bacteria. Structure-activity relationship studies revealed the importance of appropriate substituents at ICA 1-position to achieve potent inhibition to class B1 MBLs, particularly the Verona Integron-encoded MBLs (VIMs), mainly by involving ingenious interactions with the flexible active site loops as observed by crystallographic analyses. Of the tested ICA inhibitors, 55 displayed potent synergistic antibacterial activity with meropenem against engineered Escherichia coli strains and even intractable clinically isolated Pseudomonas aeruginosa producing VIM-2 MBL. The morphologic and internal structural changes of bacterial cells after treatment further demonstrated that 55 crossed the outer membrane and reversed the activity of meropenem. Moreover, 55 showed good pharmacokinetic and safety profile in vivo, which could be a potential candidate for combating VIM-mediated Gram-negative carbapenem resistance.

Discovery of new human Sirtuin 5 inhibitors by mimicking glutaryl-lysine substrates.

Human sirtuin 5 (SIRT5) plays pivotal roles in metabolic pathways and other biological processes, and is involved in several human diseases including cancer. Development of new potent and selective SIRT5 inhibitors is currently desirable to provide potential therapeutics for related diseases. Herein, we report a series of new 3-thioureidopropanoic acid derivatives, which were designed to mimic the binding features of SIRT5 glutaryl-lysine substrates. Structure-activity relationship studies revealed several compounds with low micromolar inhibitory activities to SIRT5. Computational and biochemical studies indicated that these compounds exhibited competitive SIRT5 inhibition with respect to the glutaryl-lysine substrate rather than nicotinamide adenine dinucleotide cofactor. Moreover, they showed high selectivity for SIRT5 over SIRT1-3 and 6 and could stabilize SIRT5 proteins as revealed by thermal shift analyses. This work provides an effective substrate-mimicking strategy for future inhibitor design, and offers new inhibitors to investigate their therapeutic potentials in SIRT5-associated disease models.

ProfKin: A comprehensive web server for structure-based kinase profiling.

Protein kinases are central mediators of signal-transduction cascades and attractive drug targets for therapeutic intervention. Since kinases are structurally and mechanistically related to each other, kinase inhibitor selectivity is often investigated by kinase profiling and considered as an important index for drug discovery. We here describe a versatile web server termed ProfKin for structure-based kinase profiling, which is based on a kinase-ligand focused database (KinLigDB). It provides all ready-to-use 3D structure coordinates of 4219 kinase-ligand complex structures covering 297 human kinases and the associated information, particularly including binding site type, binding ligand type, interaction fingerprints, downstream molecules and related human diseases. The web server works via predicting possible binding modes for the query molecule, prioritizing the binding modes guided by an interaction fingerprint analysis method, and giving a list of ranked kinases by a comprehensive index. Users can freely select entire or part of the KinLigDB database, e.g. via subfamily and binding site type, to customize the profiling contents. The superimpositions of the predicted binding poses of the query molecule with reference binding modes can be visually inspected on the website. The additional classification attributes and phylogenetic tree are also given for each top-ranked kinase.

AncPhore: A versatile tool for anchor pharmacophore steered drug discovery with applications in discovery of new inhibitors targeting metallo-ß-lactamases and indoleamine/tryptophan 2,3-dioxygenases.

We herein describe AncPhore, a versatile tool for drug discovery, which is characterized by pharmacophore feature analysis and anchor pharmacophore (i.e., most important pharmacophore features) steered molecular fitting and virtual screening. Comparative analyses of numerous protein-ligand complexes using AncPhore revealed that anchor pharmacophore features are biologically important, commonly associated with protein conservative characteristics, and have significant contributions to the binding affinity. Performance evaluation of AncPhore showed that it had substantially improved prediction ability on different types of target proteins including metalloenzymes by considering the specific contributions and diversity of anchor pharmacophore features. To demonstrate the practicability of AncPhore, we screened commercially available chemical compounds and discovered a set of structurally diverse inhibitors for clinically relevant metallo-ß-lactamases (MBLs); of them, 4 and 6 manifested potent inhibitory activity to VIM-2, NDM-1 and IMP-1 MBLs. Crystallographic analyses of VIM-2:4 complex revealed the precise inhibition mode of 4 with VIM-2, highly consistent with the defined anchor pharmacophore features. Besides, we also identified new hit compounds by using AncPhore for indoleamine/tryptophan 2,3-dioxygenases (IDO/TDO), another class of clinically relevant metalloenzymes. This work reveals anchor pharmacophore as a valuable concept for target-centered drug discovery and illustrates the potential of AncPhore to efficiently identify new inhibitors for different types of protein targets.

Design and enantioselective synthesis of 3-(α-acrylic acid) benzoxaboroles to combat carbapenemase resistance.

Chiral 3-substituted benzoxaboroles were designed as carbapenemase inhibitors and efficiently synthesised via asymmetric Morita-Baylis-Hillman reaction. Some of the benzoxaboroles were potent inhibitors of clinically relevant carbapenemases and restored the activity of meropenem in bacteria harbouring these enzymes. Crystallographic analyses validate the proposed mechanism of binding to carbapenemases, i.e. in a manner relating to their antibiotic substrates. The results illustrate how combining a structure-based design approach with asymmetric catalysis can efficiently lead to potent ß-lactamase inhibitors and provide a starting point to develop drugs combatting carbapenemases.