Search Results (3,751)

This study investigates the effect of dilute organic acid treatment on the structural, textural, electronic, and catalytic properties of layered La–Sr–Fe–O Ruddlesden–Popper (R–P) oxides using XRD, TEM, BET, Mössbauer spectroscopy, XPS, H₂-TPR, C₂H₆-TPR and catalytic testing. XRD and TEM confirm that the overall layered Ruddlesden–Popper structure is preserved after acid treatment and during catalysis, with minor changes in phase composition, including a decrease in the n = 1 phase and a relative increase in the n = 2 phase. BET analysis shows increased specific surface area and pore volume, forming a more accessible mesoporous structure that is retained under reaction conditions. Mössbauer spectroscopy and XPS reveal an increased Fe⁴⁺ fraction and formation of hydroxylated and carbonated surface species stabilizing active Fe sites. During catalysis, a dynamic Fe³⁺/Fe⁴⁺ redox cycle occurs, along with surface restructuring and involvement of non-lattice oxygen, while the bulk electronic structure remains largely unchanged. Catalytic tests show improved activity, with a 40–60 °C reduction in operating temperature for all acid-treated samples, independent of acid type. This enhancement is mainly attributed to surface-related modifications, including removal of surface Sr-containing species, improved surface accessibility, and enhanced mass transport, while the overall R–P structural remains preserved. Full article

The high prevalence and incidence of neurodegenerative diseases pose a public health challenge and drive the search for alternative treatments. This study determined the chemical composition of hydroalcoholic extracts from the Antarctic species Polycauliona candelaria and Placopsis antarctica and evaluated their antioxidant and cholinesterase-inhibitory potential through in vitro assays and molecular docking. Using UHPLC/ESI/QToF/MS, 16 compounds were tentatively identified in P. candelaria and 11 in P. antarctica. P. antarctica exhibited greater antioxidant capacity (2.69 ± 0.15 mg GAE/g in TPC, and an IC₅₀ for DPPH and ABTS of 330.64 ± 0.02 and 63.33 ± 0.02 µg/mL, respectively) and inhibitory activity (IC₅₀ for AChE and BuChE of 654.42 ± 0.03 and 845.58 ± 0.01 µg/mL, respectively) similar to P. candelaria. Molecular docking analyses revealed that gyrophoric acid and stictic acid possess outstanding binding affinities, comparable to the drug galantamine, by effectively interacting with the catalytic sites of the enzymes. This is the first report on the chemical compounds present in extracts of P. antarctica and P. candelaria and contributes to the understanding of their therapeutic potential. Full article

Background: Antiretroviral resistance-associated mutations, within the broader context of HIV-1 genetic variability, represent a growing challenge for HIV-1 control, highlighting the need for continuous molecular surveillance and mechanistic understanding of drug resistance. This study aimed to characterize mutations in the pol gene associated with resistance to protease inhibitors and to explore their structural implications. Methods: Viral RNA was extracted from plasma samples of HIV-positive patients, and a 266 bp fragment of the HIV-1 pol gene was amplified by RT-PCR and sequenced using the Sanger method. Sequences showing ≥98% homology were aligned and analyzed using MEGA v11 and the Stanford HIV Drug Resistance Database to identify resistance-associated mutations, while viral subtypes were determined using COMET, jpHMM-HIV, and STAR tools. Amino acid sequences were used for structural modeling with AlphaFold, followed by molecular docking with Nelfinavir using the CB-Dock2 server. Results: Four samples exhibited resistance-associated profiles, including high-level, intermediate, and low-level resistance, with one isolate showing high-level resistance to multiple protease inhibitors. Structural analyses revealed that Nelfinavir preferentially binds to alternative hydrophobic cavities rather than the canonical catalytic site, lacking direct interactions with the Asp25/Asp25′ dyad. Conclusions: These findings suggest a structural mechanism of resistance based on non-canonical ligand binding that may impair effective protease inhibition. Full article

Background: Bacterial adaptation to environmental and chemical stress involves coordinated, system-level responses collectively described as perturbome. Understanding conserved elements within core perturbomes may reveal strategic vulnerabilities for antimicrobial development. Methods: In this study, we implemented an integrative framework combining functional and comparative genomics, drug–target interactions and molecular docking to prioritize conserved stress-response targets in Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Results: A total of 147 genes from previously defined core perturbomes were analyzed through interactome reconstruction and functional enrichment. Interactome and functional analyses revealed significant connectivity and functional clustering, primarily associated with molecule biosynthesis, translation, transcriptional regulation, and energy metabolism. Orthology-based comparative genomics identified six conserved orthogroups shared across at least two species, representing key stress-adaptive nodes including fatty acid synthesis initiation, metabolic stress buffering, transcription termination (Rho), ATP synthesis, peptidoglycan remodeling, and UDP-glucose-mediated envelope biosynthesis. Drug–target interaction analyses suggested that these conserved proteins are modulated by enzymatic inhibitors, metabolite analogs, or active-site competitors. Structural and docking analyses focused on a selected protein, FabF (β-ketoacyl-ACP synthase II) and confirmed catalytically coherent binding of cerulenin within the active site, with high concordance between experimentally resolved and AlphaFold-predicted structures, supporting the reliability of structure-based prioritization. Conclusions: Overall, the results demonstrate that bacterial stress responses converge on evolutionarily conserved metabolic and regulatory elements essential for homeostasis and tolerance to perturbations, being the first work integrating core perturbome data from different microorganisms. The proposed perturbome-informed framework provides a rational strategy to identify robust, broad-spectrum antimicrobial targets and highlights opportunities for drug repurposing and future experimental validation. Full article

Sustainable water remediation requires catalytic strategies that remove contaminants efficiently while reducing chemical input, byproduct formation, and ecological disturbance. Conventional radical-dominated advanced oxidation processes can rapidly degrade pollutants, but their reliance on high oxidant dosages and freely diffusing reactive oxygen species often causes matrix quenching, non-selective oxidation, low oxidant utilization, and potential ecological risks. Mild interfacial catalysis provides a materials-chemistry strategy to regulate oxidative intensity and direct contaminant transformation under environmentally relevant conditions. In this review, mild catalysts are defined by pathway-selective, interfacially confined, and environmentally compatible oxidation rather than by low dosage alone. Representative non-radical or low-intensity pathways, including singlet oxygen generation, surface-mediated electron transfer, high-valent metal–oxo species, and direct oxidative transfer processes, are discussed in relation to active-site structure, oxidant utilization, matrix tolerance, and byproduct control. We further summarize how coordination environments, defect chemistry, heteroatom configurations, nanoconfinement, and immobilized interfaces regulate reactive-species formation and interfacial charge transfer. Key material platforms, including single-atom catalysts, heteroatom-doped carbons, defect-engineered oxides, catalytic membranes, hydrogels, and floating or immobilized composites, are evaluated from mechanistic and application-oriented perspectives. Finally, catalyst regeneration, cost, microbial community responses, algae–bacteria balance, ecotoxicity, and long-term safety are discussed to guide sustainable aquatic ecosystem restoration. Full article

Crimean–Congo hemorrhagic fever virus (CCHFV) remains a major public health threat due to its high mortality rates and the absence of approved antiviral therapies. The viral ovarian tumor (OTU) protease is a critical virulence factor that suppresses host innate immunity through its deubiquitinase activity, making it an attractive therapeutic target. In this study, we employed a structure-guided approach to identify and validate novel small-molecule inhibitors targeting the non-catalytic Y89-W99 pocket of the OTU protease. Recombinant OTU protease was successfully expressed, purified, and refolded, yielding a soluble and enzymatically active protein. Cellular assays confirmed that the enzyme retains robust deubiquitinase activity, significantly reducing global ubiquitin conjugates in mammalian cells. In silico analysis of a putative DUB inhibitor library identified several candidate inhibitors with favorable binding interactions within the Y89-W99 pocket. Biochemical validation using a fluorometric Ub-AMC assay revealed that multiple small molecules strongly inhibit OTU activity, including OTUi-10 (~93% inhibition), OTUi-13 (~87%), OTUi-1 (~85%), OTUi-4 and OTUi-11 (~81%), and OTUi-9 (~76%). Additional moderate inhibitors included OTUi-12 (~67%), OTUi-19 and OTUi-21 (~66%), and OTUi-5 (~57%). In silico drug-likeness and toxicity profiling filtered the library to four fully compliant candidates, OTUi-4, OTUi-10, OTUi-11, and OTUi-12, all free of predicted toxicity alerts. These findings suggest that the Y89–W99 pocket may be a pharmacologically relevant site worthy of further investigation and identify OTUi-10, OTUi-4, and OTUi-11 as promising preliminary hit compounds. The results also provide initial insights that may guide future optimization and mechanistic studies of OTU protease inhibitors targeting CCHFV. Full article

Across all kingdoms of life, ribosomes are indispensable molecular machines that translate genetic information into the proteome of living cells. The fundamental catalytic centers of the ribosome, constructed primarily from ribosomal RNA (rRNA), exhibit remarkable conservation between the major domains of life. The ribosome’s A-site deciphers the mRNA’s triplet code, while the P-site synthesizes the growing protein chain and the E-site provides exit for deacylated tRNA; a distinct tunnel facilitates nascent polypeptide export. While the conservation of ribosomal proteins is less pronounced between bacteria and eukaryotes, striking homology exists from simple eukaryotes to humans. Ribosomal proteins were traditionally viewed mainly as scaffolding agents, steering rRNA folding during ribosome biogenesis and maintaining structural stability during translation. However, since the early 2000s, advances in structural and functional ribosome analysis have ushered in a more nuanced paradigm: ribosomes are no longer considered uniform machines. Instead, an array of rRNA and ribosomal protein modifications generates a spectrum of ribosome populations capable of specialized translation. RiboScreen^TM technology leverages this regulatory potential of individual ribosomal proteins, enabling deliberate modulation of target protein output and representing a promising tool for correcting dysregulated protein expression involved in rare and common diseases. This review will first introduce relevant aspects of ribosome biology and then showcase the tools of this new technology. Finally, we report examples for the delivery of small molecules to target ribosomal proteins for tailored restoration of protein production levels in rare and prevalent diseases. Full article

The practical application of Li–O₂ batteries is severely hindered by parasitic reactions on the cathode side, which generally lead to large charging over-potentials and degraded cyclic performance. To address this issue, it is essential to integrate high-efficiency catalysts into conventional carbon-based electrodes. Herein, we report a novel La_0.85Ca_0.15Cr_0.85O₃@Ru (LCC@R) hybrid catalyst with an ultralow Ru loading (6.55 wt.%), synthesized via a facile sol-gel combined with in-situ reduction-exsolution method. Mono-dispersed and ultrafine Ru nanocrystals (2–5 nm) are uniformly anchored on the LCC substrate and serve as the catalytically active sites. The Li–O₂ battery with the LCC@R catalyst exhibits a low charge potential of 3.75 V at a current density of 50 mAg⁻¹ with limited capacity of 500 mAhg⁻¹. Impressive cyclic stabilities of up to 80 cycles (at 1000 mAhg⁻¹) and 15 cycles (at 2000 mAhg⁻¹) are achieved. Moreover, a large specific capacity of 8630 mAhg⁻¹ is delivered at 50 mAg⁻¹. Mechanistic studies reveal that the intermediate discharge product LiO₂ can be absorbed on LCC@R, thereby inhibiting the parasitic reactions induced by LiO₂ attack on carbon. The as-prepared LCC@R hybrid material is a promising cathode catalyst for constructing long-cycle-life and low-over-potential Li–O₂ batteries. Full article

Incorporating comonomers in propylene polymerization plays a critical role in tuning the physical and chemical properties of the resulting polymers. In this study, the impact of three developed comonomers on propylene polymerization over the triethylaluminum-treated TiCl₃ catalyst was investigated in detail by DFT. The results indicate that these comonomers remain highly stable under actual catalytic conditions, with their ions or functional groups showing a low propensity for detachment, which would otherwise poison the catalyst or disrupt the polymerization process. However, the three comonomers on the surface with a strong adsorption capacity may compete with propylene for adsorption, which will affect the polymerization. Among them, Vinyltrimethoxysilane, which exhibits the strongest adsorption ability, tends to form bonds with the ethyl on the catalyst surface, leading to catalyst poisoning and inhibiting the reaction. In contrast, 5-hexenyl methyldichlorosilane demonstrates relatively higher activity due to its balanced properties. The order of reactivity in the polymerization reaction: 5-hexenyl methyldichlorosilane > 5-hexenyldichlorophosphonane > vinyltrimethoxysilane. This work provides fundamental mechanistic insights into how functional comonomers interact with catalytic active sites through adsorption, competitive reactions, and insertion processes. Additional free energy analysis at 333 K confirms that these mechanistic trends remain unchanged under realistic reaction conditions. Rather than directly simulating industrial catalysts, the present study focuses on a model TiCl₃ system to elucidate intrinsic structure-reactivity relationships. These findings contribute to a deeper understanding of comonomer effects in olefin polymerization at the molecular level. Full article

Perillyl alcohol, a rare monoterpenoid, can be widely used in chemical, agriculture, and food industries and shows promise in medicine as an anticancer agent. The artificial synthesis of perillyl alcohol from β-pinene epoxide using inexpensive and abundant turpentine is chosen for improving its pharmaceutical and industrial applications. This work presents a green and sustainable catalytic process for the rearrangement of β-pinene epoxide to perillyl alcohol. A novel ammonium phosphomolybdate solid acid (AC-COIMI-NH₄PMo) was built via phosphomolybdic acid chemisorption onto an N-basylous site of imidazolized activated carbon followed by ammonia fumigation, which exhibits outstanding catalytic performance in the rearrangement of β-pinene epoxide to perillyl alcohol in nitromethane under mild conditions. At 80 °C over 80 min, nearly complete conversion of the epoxide is achieved with a perillyl alcohol selectivity of 77.3%. Moreover, the used catalyst can be readily recycled after washing with hot nitromethane. The favorable proton-donating capacity of nitromethane for the rearrangement and the comparison of adsorption energies between substrates and main products on ammonium phosphomolybdate are revealed through DFT calculation. Kinetic analysis based on the Langmuir adsorption model indicates that the surface reaction of strongly adsorbed β-pinene epoxide is a rate-determining step and follows a zero-order reaction process; the activation energy is 29.64 kJ/mol within the temperature range of 50–80 °C. Finally, a parallel catalytic rearrangement mechanism is proposed, and an eight-step reaction pathway toward perillyl alcohol is elaborated for β-pinene epoxide conversion on AC-COIMI-NH₄PMo. Full article

Coniferyl alcohol and coniferyl aldehyde are precursors of lignin and are used in spices and the pharmaceutical industry. In this work, antioxidant, anticholinergic, antidiabetic, and antiglaucoma effects of coniferyl alcohol and aldehyde were evaluated and compared against the standards. To determine the antioxidant capacities of coniferyl alcohol and aldehyde, ABTS^•+, DMPD^•+ and DPPH^• scavenging abilities as well as cupric ion (Cu²⁺) reduction, ferrous ions (Fe²⁺) reduction and Fe³⁺-TPTZ reduction activities were studied. Butylated hydroxytoluene (BHT), ascorbic acid, α-Tocopherol, Trolox, and butylated hydroxyanisole (BHA) were used as the standard antioxidants. When the antioxidant effects of coniferyl alcohol and coniferyl aldehyde are compared to the standards, they exhibit significant antioxidant effects. In addition, it was determined that coniferyl alcohol and coniferyl aldehyde had a high degree of inhibition effect towards carbonic anhydrase (hCA) I and II isoforms purified from human erythrocytes, α-glycosidase, butyrylcholinesterase (BChE), acetylcholinesterase (AChE), and α-amylase as in vitro and in silico. Molecular docking studies revealed favorable binding affinities of coniferyl alcohol and coniferyl aldehyde toward all investigated enzymes, with key hydrogen bonding and π–π interactions identified at the active sites. The docking findings were found to be compatible with the in vitro enzyme inhibition results, supporting the proposed multi-target biological potential of both compounds. Molecular docking studies revealed favorable binding affinities of coniferyl alcohol and coniferyl aldehyde toward all investigated enzymes. Key hydrogen bonding and π–π interactions were identified within the active sites, particularly for AChE and hCA II. The docking results were consistent with the in vitro enzyme inhibition data, supporting their multi-target biological potential. Docking demonstrated that both compounds can effectively interact with the catalytic regions of the target enzymes. The identified binding modes and interaction patterns support the observed inhibitory activities and provide a molecular basis for their multi-target biological effects. Full article

Machupo virus (MACV) is the causal agent of Bolivian Hemorrhagic fever. It is highly pathogenic, has a high mortality rate, and currently lacks specific treatments or vaccines. MACV belongs to the Arenaviridae family, which uses a cap-snatching mechanism during the transcription process. Its viral polymerase, the L protein, harbors the endonuclease activity required for cap snatching, making it a suitable target for the development of antiviral therapeutics. We combined experimental and computational methods to characterize MACV endonuclease activity and evaluate inhibitors. A fluorescence resonance energy transfer (FRET) assay was used to measure the enzymatic activity of endonuclease and identify potent inhibitors via high-throughput screening. FRET assays identified BW-148, an inhibitor with a 48.4 µM (95% CI: 37.3–59.3 µM; R² = 0.98) IC₅₀, and a K_D of 13.7 µM (95% CI: 8.2–19.2 µM, n = 3). Docking studies reveal that BW-148 may bind near the MACV endonuclease catalytic site, inhibiting enzymatic activities by metal chelating. BW-148 is a useful lead compound for further optimization of Machupo endonuclease inhibitors. Full article

The influence of carbon support and Cu loading on the structural, surface, and catalytic properties of Cu-based catalysts for furfural hydrogenation was systematically investigated. Two activated carbons with distinct textural and chemical characteristics were evaluated: a biomass-derived carbon (ACS) and commercial carbon (ACC). The ACC support exhibited a higher density of thermally stable oxygen-containing functional groups, which promoted stronger metal-support interactions and an increased proportion of surface reduced Cu species (Cu⁰/Cu⁺), resulting in superior catalytic performance compared to ACS. Based on these results, the effect of Cu loading (5–20 wt.%) was further studied on the ACC support. The catalysts were characterized by N₂ physisorption, XRD, TEM, H₂-TPR, He-TPD, NH₃-TPD, and XPS. Increasing Cu loading enhanced the amount and reducibility of Cu species; however, excessive loading led to particle growth, pore blockage, and reduced metal dispersion. Catalytic activity exhibited volcano-type behavior, reaching a maximum at 15 wt.% Cu, where an optimal balance between reduced availability of Cu species and metal-support interaction was achieved. Selectivity toward furfuryl alcohol remained essentially unchanged across all catalysts, indicating that the catalytic performance is closely related to the surface chemistry and relative concentration of reduced Cu sites and is not significantly affected by acidity. These results highlight the critical role of support properties and metal loading in controlling catalyst performance, providing insights for the rational design of efficient Cu-based catalysts for biomass valorization. Full article

Demand for greener and safer chemistries has driven the innovation of bioinspired and enzyme-mimicking catalysts for selective and efficient oxidation and hydrogenation under mild conditions. Natural catalysts, including peroxidases, oxidases, hydrogenases, oxygenases and dehydrogenases, boast remarkable activity, specificity, stability, selectivity, low energy requirements and atom economy. Disadvantages of enzymes, such as poor thermal stability, a narrow operational range, low recovery yield and the expense of purification, are motivating the discovery and design of enzyme substitutes. Several artificial platforms have appeared recently: nanozymes, artificial metalloenzymes, biomimetic metal Complexes, MOFs, atomic catalysts, bioinorganic hybrid systems, among others. These systems aim to replicate key structural and mechanistic features of enzymes while providing greater operational stability, recyclability, and scalability. Recent work has demonstrated the benefit of enzyme mimics in increasing eco-sustainability in reactions such as alcohol oxidation, selective alkane oxidation, waste degradation, catalytic photooxygen activation and biomass waste conversion. Similarly, biomimetic hydrogenation catalysts have shown outstanding activity in asymmetrically hydrogenating chemicals, reducing CO₂ into chemicals, hydrogenation by hydrogen transfer and creating hydrogen through water. Through control of active sites, second coordination sites, defects and electrons/protons in the system, significant gains have been seen in reaction selectivity and frequency of turning over substrate into product. Nanozymes, biohybrid catalysis and artificial catalysts guided by deep learning are further broadening the applications of biomimetic catalysis in oxidation and hydrogenation. The article review aims to provide a summary of the most current progress with bioinspired and enzyme-mimicking catalysts, focusing on catalytic mechanisms, how to design such catalysts, how green chemistry benefits from their development and where further application is likely in the coming years. Full article

Ubiquitin-specific protease 22 (USP22) regulates epigenetic gene expression by deubiquitinating histone H2B (H2Bub1) and upregulating oncogenic proteins and pathways, while antagonizing p53-mediated tumor suppression. USP22 is frequently overexpressed in cancers and associated with therapy resistance and poor prognosis yet remains largely untargeted pharmacologically. Here, using a fluorescence-based USP22 deubiquitinase assay to screen the LOPAC^®1280 library, we identified β-Lapachone, a natural ortho-naphthoquinone with strong anticancer activities, as a potent USP22 inhibitor. β-Lapachone potently inhibited USP22 enzymatic activity, with a half-maximal inhibitory concentration (IC₅₀) of ~0.75 μM, and molecular docking revealed its occupation of the catalytic pocket adjacent to the USP22 active-site triad, supporting a potential binding mode. Functionally, β-Lapachone suppressed proliferation and induced apoptosis in A549 and H1299 RAS-mutant lung adenocarcinoma (LUAD) cells, while USP22 knockout conferred marked resistance, indicating partial USP22 dependence. In patient-derived LUAD models, β-Lapachone inhibited sphere formation and reduced CD133⁺ cancer stem cell populations. Notably, it synergized with cisplatin to enhance DNA damage and apoptosis. In vivo, β-Lapachone significantly suppressed tumor growth in a syngeneic KRAS-mutant/p53-Null mouse lung cancer model and further potentiated cisplatin-induced antitumor effects. Collectively, these findings identify β-Lapachone as a potent inhibitor of USP22 and validate USP22 inhibition as a key mechanism underlying its anticancer activity in LUAD cells, both in vitro and in vivo. Full article