In situ visualization of cardiolipin (CL) is critical for understanding mitochondrial function but remains limited by a lack of specific probes. Here, we report DHX-CL as the first wash-free, V-shaped near-infrared (NIR) probe specifically engineered for high-contrast in situ detection of cardiolipin. Molecular dynamics simulations and spectroscopic studies confirm that DHX-CL achieves exceptional selectivity through electrostatic and topological complementarity, with fluorescence activation triggered by restricted twisted intramolecular charge transfer (TICT). In live cells, DHX-CL outperforms the standard dye Nonyl Acridine Orange (NAO) regarding photo-stability and biocompatibility. Notably, it enables wash-free imaging and retains mitochondrial localization independent of membrane potential (Delta psi m). Collectively, this work establishes a mechanistically validated strategy for wash-free cardiolipin imaging, offering a powerful molecular tool and a new conceptual framework for probing mitochondrial lipid biology in living systems.

Abnormal mitochondrial viscosity is closely associated with a wide range of diseases and cellular dysfunction. It is crucial to develop fluorescent probes for precisely monitoring changes of mitochondrial viscosity in the detection and treatment of associated diseases. However, mitochondria-targeted fluorescent probes currently faced off-target problems because their high water-solubility could hinder the accurate detection of mitochondrial viscosity. Herein, a viscosity-sensitive fluorescent probe, HPQ-MV was designed and synthesized in this work. The indole cation and HPQ (2-(2 '-hydroxyphenyl)-4(3H)-quinazolinone) moiety were introduced could make the probe HPQ-MV have excellent mitochondrial targeting properties and reduce the aqueous solubility of HPQ-MV made the probe less susceptible to diffusion, respectively. When the mitochondrial membrane potential was decreased, HPQ-MV could remain stable in the mitochondria and not cause false-negative signals. HPQ-MV had a signal-to-noise ratio of up to 2900-fold with respect to viscosity which was unaffected by pH and polarity. Additionally, HPQ-MV possessed a tissue permeability of up to 62.6 mu M and had effectively facilitated in vivo imaging of fatty liver, inflammation, and in situ tumors.

Pyridoxal 5'-phosphate (PLP) plays an essential role in a multitude of cellular processes due to its function as a critical coenzyme. This study introduces a significant advancement in PLP biosynthesis by enhancing the stability and activity of Escherichia coli-derived pyridoxal kinase (EcPdxK) through immobilization on an innovative epoxy resin, LXTE-600. Our approach involved the systematic optimization of enzyme loading, coupling duration, and temperature, which resulted in improved immobilization efficiency and a high loading capacity of 80 mg/g. The characterization of immobilized EcPdxK@LXTE-600 was conducted using Fourier transform infrared spectroscopy (FTIR) and confocal laser scanning microscopy (CLSM), confirming successful immobilization. This process notably enhanced the enzyme's performance, increasing its tolerance to pH and temperature fluctuations, thereby improving its thermal stability. The immobilized EcPdxK@LXTE-600 retained over 80% of its initial activity after 4 weeks of storage at 4°C and could be reused up to eight cycles while maintaining more than 70% of its initial activity. These findings not only demonstrate the efficacy of the LXTE-600-based immobilization method but also suggest promising industrial applications for the sustainable production of PLP, potentially revolutionizing approaches in biotechnological and pharmaceutical sectors.

Nitrogen-containing compounds, particularly those with chiral amine structures, play a crucial role in the development of organic active pharmaceutical ingredients. Imine reductases (IREDs), NAD(P)H-dependent enzymes that catalyze the reduction of cyclic imines and the reductive amination of prochiral ketones, offer significant industrial potential for the synthesis of chiral amines. However, despite the growing body of research, a comprehensive and unbiased assessment of IRED research remains lacking. This study aims to explore the research landscape and evolution of IREDs using bibliometric and knowledge mapping methods. A total of 239 research articles and reviews on IREDs, published between 2010 and 2024, were retrieved from the Web of Science Core Collection and analyzed using tools such as CiteSpace, VOSviewer, Pajek, and Scimago Graphica. Results showed a consistent increase in both publications and citations, with a sharp rise since 2014. Collaboration network analysis revealed that the United Kingdom leads the field in terms of publications and influential institutions, while ChemCatChem was identified as the journal with the highest number of articles. Nicholas J. Turner emerged as a key researcher, having published the most papers and achieving the second-highest citation frequency. Research trends and keyword analysis highlighted areas of focus such as IRED crystal structure resolution, protein engineering modifications, and expanded industrial applications, including multi-enzyme cascade reactions. Ongoing advancements in synthetic biology, protein modifications, and enzyme engineering are expected to drive further studies on highly active IREDs for asymmetric synthesis of pharmaceutical compounds, positioning this research at the forefront of the field. By employing bibliometric analysis, this study provides the first visual representation of IRED research, offering valuable insights into current trends and emerging topics that will aid scholars in identifying key research areas and potential collaborators.

Pulmonary fibrosis (PF) is a progressive and refractory lung disease characterized by fibrosis that can result in the accumulation of extracellular matrix, impair alveolar elasticity, and consequently increase mortality. Superoxide anion (O2 center dot- ), as one of the initial intracellular reactive oxygen species, plays a pivotal role in cell signaling networks and redox homeostasis. Abnormal levels of this species can directly reflect the state of intracellular oxidative stress. Nevertheless, the relationship between O2 center dot- and PF has remained unclear. Accordingly, a fluorescent probe, designated SOACHO, was devised and constructed for the purpose of detecting O2 center dot-. The fluorescence emission peak of SOACHO in response to O2 center dot- was observed to occur at a wavelength of 627 nm. The SOACHO demonstrated high specificity and sensitivity to O2 center dot- , with a response time of less than 300 seconds and a detection limit of 12 nM. SOACHO was capable of specifically detecting the endogenous O2 center dot- levels in cells without interference from nucleophilic reagents and oxidants, and subsequently monitoring the levels of O2 center dot- in oxidative stress and pulmonary fibrosis cell models. Furthermore, SOACHO was able to monitor the levels of O2 center dot- in the lungs of mice in real-time, providing insights into the progression of pulmonary fibrosis. The severity of pulmonary fibrosis was found to be positively correlated with O2 center dot- , as evidenced by the correlation with hydroxyproline content, lung coefficients, histopathological observations, and immunohistochemical analyses. The aforementioned results may offer a novel perspective on the early treatment of pulmonary fibrosis.

Type I photodynamic therapy (PDT), generating superoxide anion radicals (O2•-), presents a potent strategy against tumor resistance by virtue of its low oxygen dependence, ensuring efficacy in hypoxic tumors where traditional Type II PDT is limited. However, accurate O2•- detection with high spatiotemporal and subcellular resolution remains a critical unmet need. Herein, we report the rational design and synthesis of HPQ-CF3, a novel fluorescent probe. Upon selective reaction with O2•-, HPQ-CF3's trifluoromethanesulfonate group departs, unmasking a hydroxyl group to generate the highly fluorescent HPQ-OH, a fluorophore incorporating the HPQ moiety. Crucially, the inherent low aqueous solubility of HPQ-OH leads to its in situ precipitation, enabling precise spatial localization of O2•- generation sites. HPQ-CF3 exhibits high specificity, a rapid response (<300 s), a remarkable ∼200-fold fluorescence enhancement, a low limit of detection (LOD, 0.13 μM), and excellent linearity. HPQ-CF3 demonstrated significantly superior performance over the commercial probe DHR123 for intracellular O2•- detection; its unique precipitation-based mechanism inherently minimizes background fluorescence while anchoring the signal at its origin, affording a substantially enhanced signal-to-noise ratio and markedly improved localization accuracy. Furthermore, HPQ-CF3 successfully monitored O2•- production in complex biological settings, including solid tumors. HPQ-CF3 is anticipated to be an invaluable tool for investigating O2•--related pathophysiology and advancing Type I photosensitizer development.

Cadmium, as a toxic heavy metal, could largely accumulates in the soil which resulted in the absorption of plants affecting the growth. Furthermore, it could pose a threat to human health through the food chain, resulting in kidney damage and related disease. Therefore, it is of the utmost importance to develop a peptide fluorescent probe to detect cadmium ions in a sensitive and rapid manner. In this work, a peptide fluorescent probe, TPE-EG (TPE-Gly-Glu-Phe-Cys), was developed which could specifically monitor Cd2+ through the aggregation-induced emission (AIE) effect. The fluorescence intensity of the fluorescent probe TPE-EG was significantly increase after reacted with Cd2+ ions. The peptide probe TPE-EG exhibited high sensitivity with a detection limit of only 214 nM, good tissue permeability (60 mu m), and good biocompatibility. In addition, the peptide probe TPE-EG could monitor Cd2+ in the natural water quality, aquatic organisms (zebrafish), the aggregation of Cd2+ ions in plants, and renal damage caused by cadmium toxicity in vivo. Therefore, the probe TPE-EG could provide a theoretical basis for monitoring cadmium levels and a tool for detecting cadmium in various fields.

Self-assembling peptide (SAP) tags induce protein self-assembly, forming insoluble protein aggregates. Traditional l-citrulline production using arginine deiminase (ADI) is limited by enzyme instability and low reusability. SAP tags were fused with ADI to overcome these challenges, and ADI-ELK16 demonstrated optimal activity at 55 °C and pH 6.0 with enhanced thermal stability. ADI-ELK16 retained 57.34% of its enzyme activity after 10 cycles, with notable reusability. The protein was characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), and the zeta potential. Additionally, the conversion of 100 g/L l-arginine to 92.3 g/L l-citrulline over batch reactions validated the industrial potential of ADI-ELK16. Compared with traditional immobilization methods, this approach eliminates the need for carrier materials, simplifying the immobilization process and significantly enhancing the catalytic performance and stability, making ADI-ELK16 a highly efficient and reusable system for industrial applications.

Carbon monoxide (CO) is a recently discovered gasotransmitter. In animals, it has been found that endogenously produced CO participates in the regulation of various metabolic processes. Recent research has indicated that CO, acting as a signaling molecule, plays a crucial regulatory role in plant development and their response to abiotic stress. In this work, we developed a fluorescent probe, named COP (carbonic oxide Probe), for the in situ imaging of CO in Arabidopsis thaliana plant tissues. The probe was designed by combining malononitrile-naphthalene as the fluorophore and a typical palladium-mediated reaction mechanism. When reacted with the released CO, COP showed an obvious fluorescence enhancement at 575 nm, which could be observed in naked-eye conditions. With a linear range of 0-10 μM, the limit of detection of COP was determined as 0.38 μM. The detection system based on COP indicated several advantages including relatively rapid response within 20 min, steadiness in a wide pH range of 5.0-10.0, high selectivity, and applicative anti-interference. Moreover, with a penetration depth of 30 μm, COP enabled 3D imaging of CO dynamics in plant samples, whether it was caused by agent release, heavy metal stress, or inner oxidation. This work provides a fluorescent probe for monitoring CO levels in plant samples, and it expands the application field of CO-detection technology, assisting researchers in understanding the dynamic changes in plant physiological processes, making it an important tool for studying plant physiology and biological processes.

Acute lung injury (ALI) is a serious pulmonary inflammatory disease resulting from excessive reactive oxygen species (ROS) which could cause the damage of the alveolar epithelial cells and capillary endothelial cells. Peroxynitrite, as one of short-lived reactive oxygen species, is closely related to the process of ALI. Thus, it is important to monitor the fluctuation of peroxynitrite in living system for understanding the process of ALI. Herein, the novel mitochondria-targeted fluorescent probe BHMT was designed to respond to peroxynitrite and pH with distinct fluorescence properties respectively. The absorption spectrum of the probe BHMT exhibited a notable red shift as the pH value declined from 8.8 to 2.6. Upon reaction with peroxynitrite, BHMT had a significant increase of fluorescence intensity (63-fold) with maintaining a detection limit of only 43.7 nM. Furthermore, BHMT could detect the levels of endogenous peroxynitrite and image the intracellular pH in ratiometric channels utilizing cell imaging. In addition, BHMT was successfully applied to revealing the relationship between the peroxynitrite and the extent of ALI. Thus, these results indicated the probe BHMT could be a potential tool for diagnosing the early stage of ALI and revealed the peroxynitrite was likely to be a crucial therapeutic target in ALI treatment.

Thermostability is considered a crucial parameter to evaluate the viability of enzymes in industrial applications. Over the past 31 years, many studies have been reported on the thermostability of enzymes. However, there is no systematic bibliometric analysis of publications on the thermostability of enzymes. In this study, 16,035 publications related to the thermostability of enzymes were searched and collected, showing an increasing annual trend. China contributed the most publications, while the United States had the highest citation count. International Journal of Biological Macromolecules is the most productive journal in the research field. Moreover, Chinese acad sci and Khosro Khajeh are the most active institutions and prolific authors in the field, respectively. Analysis of references with the strongest citation bursts and keyword co-occurrences, magnetic nanoparticles, metal–organic frameworks, molecular dynamics, and rational design are current hot spots and significant future research directions. This study is the first comprehensive bibliometric analysis summarizing trends and developments in enzyme thermostability research. Our findings could provide scholars with an understanding of the fundamental knowledge framework of the field and identify recent potential hotspots and research trends that could facilitate the discovery of collaboration opportunities.

Cancer poses a significant global health challenge and significantly contributes to mortality. NEK7, related to the NIMA protein kinase family, plays a crucial role in spindle assembly and cell division. The dysregulation of NEK7 is closely linked to the onset and progression of various cancers, especially colon and breast cancer, making it a promising target for cancer therapy. Nevertheless, the shortage of high-quality NEK7 inhibitors highlights the need for new therapeutic strategies. In this study, we utilized a multidisciplinary approach, including virtual screening, molecular docking, pharmacokinetics, molecular dynamics simulations (MDs), and MM/PBSA calculations, to evaluate natural compounds as NEK7 inhibitors comprehensively. Through various docking strategies, we identified three natural compounds: (−)-balanol, digallic acid, and scutellarin. Molecular docking revealed significant interactions at residues such as GLU112 and ALA114, with docking scores of −15.054, −13.059, and −11.547 kcal/mol, respectively, highlighting their potential as NEK7 inhibitors. MDs confirmed the stability of these compounds at the NEK7-binding site. Hydrogen bond analysis during simulations revealed consistent interactions, supporting their strong binding capacity. MM/PBSA analysis identified other crucial amino acids contributing to binding affinity, including ILE20, VAL28, ILE75, LEU93, ALA94, LYS143, PHE148, LEU160, and THR161, crucial for stabilizing the complex. This research demonstrated that these compounds exceeded dabrafenib in binding energy, according to MM/PBSA calculations, underscoring their effectiveness as NEK7 inhibitors. ADME/T predictions showed lower oral toxicity for these compounds, suggesting their potential for further development. This study highlights the promise of these natural compounds as bases for creating more potent derivatives with significant biological activities, paving the way for future experimental validation.

Breast cancer lung metastases (BCLM) are a major cause of high mortality in patients. The shortage of therapeutic targets and rapid drug screening tools for BCLM is a major challenge at present. Mitochondrial autophagy, which involves the degradation of proteins associated with cancer cell aggressiveness, represents a possible therapeutic approach for the treatment of BCLM. Herein, four fluorescent biosensors with different alkyl chains were designed and synthesized to monitor mitochondrial autophagy. Among them, PMV-12 demonstrated the highest sensitivity to viscosity variance, the least impact on polarity, and the longest imaging time. The introduction of the C12-chain made PMV-12 anchored in the mitochondrial membrane without being disturbed by changes of the mitochondrial membrane potential (MMP), thereby achieving the long-term monitor in situ for mitochondrial autophagy. Mitochondria stained with PMV-12 induced swelling and viscosity increase after treating with apigenin, which indicated that apigenin is a potential mitochondrial autophagy inducer. Apigenin was subsequently verified to inhibit cancer cell invasion by 92%. Furthermore, PMV-12 could monitor the process of BCLM in vivo and evaluate the therapeutic effects of apigenin. This work provides a fluorescent tool for elucidating the role of mitochondrial autophagy in the BCLM process and for anti-metastatic drug development.

Acute liver injury as a serious inflammatory liver disease has a high morbidity and mortality rate. For drug treatment for acute liver injury, the focus was mainly from oxidative stress and rarely from a reductive perspective over the past decades. Herein, a novel quinoline-malononitrile-based fluorescent probe (QM-NA) designed for high efficiency sensitive detection of NAD(P)H, a critical marker related to reductive stress. QM-NA exhibited high selectivity for NADPH as well as a fast "turn-on" fluorescence response (4min) with a Stokes shift of 77nm, a detection limit of 18nM, and favorable biocompatibility for cell-based experiments. With QM-NA in hand, the fluorescence imaging of endogenous and exogenous NADPH at the cellular level was achieved. More importantly, in vivo experiments demonstrated QM-NA was successfully used to visualize the fluctuations of NADPH and evaluate the efficacy of three antioxidants for the first time in acute liver injury mice. These above results afford a novel strategy for the treatment of acute liver injury and this probe is expected to be a promising molecular tool to evaluate the efficacy of hepatoprotective drugs.

The strategies based on enzyme immobilization into/on metal-organic frameworks (MOFs) have been widely developed, but they still face some challenges in practical applications, such as limited recycle times, low loading efficiency. In this work, aspartate aminotransferase (AspAT), branched-chain aminotransferase (BCAT), polyvi-nyl pyrrolidone/aspartate (PA), cobalt ions and sodium 2-amino terephthalate were one-pot mixed in water at room temperature, and self-assembled to encapsulate the enzymes into cobalt-amino terephthalate framework (CAF) in 15 min. Compared with free enzymes, the biocomposite (A&B&PA@CAF) exhibited superior perfor-mances such as high encapsulation efficiency (55%), reusability (>= 12), and resistance capacity to harsh con-ditions. Meanwhile, the activity recovery (AR) value (59.4%) of the biocomposite without adding polyvinyl pyrrolidone and aspartate was almost half of that (108.2%) of A&B&PA@CAF, and this enhancement was further demonstrated to be from Asp action via 1H-NMR and UV-Vis. To investigate the general applicability of this approach, the other aminases were also de novo immobilized with all their AR values reached more than 117%, even 180% for omega-transaminase. This study provided a sustainable and green approach for clean production of the significant chiral amine compounds.

Abstract Cancer remains a significant health problem and stands as one of the primary causes of death worldwide. NEK7, a NIMA-related protein kinase, plays a crucial role in spindle assembly and cell division. Dysregulation of the NEK7 protein contributes to the development and progression of various malignancies, such as colon cancer and breast cancer. Therefore, the inhibition of NEK7 shows promise as a potential clinical target for anticancer therapy. Nevertheless, there is a dearth of high-quality NEK7 inhibitors. In this study, we utilized virtual screening, molecular docking, silicon-based pharmacokinetics, molecular dynamics (MD) simulations, and molecular mechanics Poisson-Boltzmann surface area (MM/PBSA)-based binding free energy calculations to comprehensively analyze effective natural inhibitors that target NEK7 within the current framework. By employing molecular docking, including semi-flexible and flexible docking methods, we identified three natural products as hit compounds with binding modes similar to the active control dabrafenib. ADME/T predictions indicated that these hit molecules exhibited lower toxicity when administered orally. Additionally, through DFT calculations, we determined that the popular compound (-)-balanol possessed high chemical activity. Finally, 100 ns molecular dynamics simulations and energy decomposition revealed that the hit compounds displayed superior binding energy compared to the active control and demonstrated higher affinity. Based on the findings of our current research, we conclude that these newly discovered natural inhibitors may serve as parent structures for the development of more potent derivatives with promising biological activities. However, further experimental validation is necessary as part of subsequent investigations.

European Journal of Medicinal Chemistry (EJMC) has been around for a long time and has gained broad interest from the various individuals working in the field. However, there is no bibliometric analysis on the publications of EJMC to thoroughly assess the scientific output and current status systematically. Therefore, the study was conducted to analyze the various publications of EJMC from 1987 to 2022 to improve their quality. A total of 13,386 papers were retrieved, with the number of publications increasing yearly. Based on the multiple indicators of bibliometrics, the highest impact countries, institutions, authors and representative literature were identified, and visualization networks were constructed using VOSviewer. Keyword co-occurrence analysis reveals a gradual shift from phenotypic drug discovery to target-based drug discovery in the EJMC theme change. Moreover, further discussion of the keyword clustering results is provided to support researchers in defining the scope of their research topics and planning their research directions. At this stage, there is a greater focus on developing antitumor and oxidative stress-related drugs than on the earlier anti-infective activities. In future studies, the main research directions are tumor multidrug resistance, oxidative stress, and dual inhibitors.

As an excellent biocatalyst, aromatic L-amino acid decarboxylase from Bacillus atrophaeus ( BaAADC) catalyzes the production of various vital aromatic biogenic amines. However, its weak heat resistance makes BaAADC unsuitable for industrial production. Here, we have generated the three-dimensional structure of BaAADC and used molecular dynamics simulations to examine the dynamic behaviour of BaAADC at various temperatures (303, 313, 323, 333, and 343 K) to determine the connection between its thermal stability and internal residues. We have shown that the natural structure of BaAADC is altered at high temperatures, with more striking alterations in secondary structure, decreased internal hydrogen bonding, and greater amino acid flexibility in certain areas. In addition, strategies to improve the thermostability of BaAADC are discussed. This research might provide light on the development and modification of heat-resistant ability BaAADC.

As a precursor of all reactive oxygen species (ROS), superoxide anions play an important role in organisms. However, excessive superoxide anions can cause various diseases. Thus, it is highly urgent to develop efficient tools for in situ superoxide anion detection. In this work, a novel boric acid-based, mitochondria-targeted fluorescent probe Mito-YX for superoxide anion detection was designed by regulating its intramolecular charge transfer (ICT) effect. The probe exhibited turn-on fluorescence enhancement within 4 min of reaction with the superoxide anion. In addition, Mito-YX also exhibited high selectivity and a low detection limit down to 0.24 μM with good mitochondrial targeting characteristics, which provided a necessary basis for in vivo detection of superoxide anions. What is more, Mito-YX was successfully applied for the in situ monitoring of superoxide anions in living MCF-7 cells, RAW 264.7 cells and a mouse model of lung inflammation stimulated by LPS. This work provided an important and promising tool for rapid in situ diagnosis and research of the progression of pneumonia.

Correction for ‘A highly selective AIEgen fluorescent probe for visualizing Cys in living cells and C. elegans’ by Ya-Xi Ye et al., New J. Chem., 2021, 45, 19073–19081.