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Amyloid β (Aβ) peptides accumulating in the brain are proposed to trigger Alzheimers disease (AD). However, molecular cascades underlying their toxicity are poorly defined. Here, we explored a novel hypothesis for Aβ42 toxicity that arises from its proven affinity for γ-secretases. We hypothesized that the reported increases in Aβ42, particularly in the endolysosomal compartment, promote the establishment of a product feedback inhibitory mechanism on γ-secretases, and thereby impair downstream signaling events. We conducted kinetic analyses of γ-secretase activity in cell-free systems in the presence of Aβ, as well as cell-based and ex vivo assays in neuronal cell lines, neurons, and brain synaptosomes to assess the impact of Aβ on γ-secretases. We show that human Aβ42 peptides, but neither murine Aβ42 nor human Aβ17-42 (p3), inhibit γ-secretases and trigger accumulation of unprocessed substrates in neurons, including C-terminal fragments (CTFs) of APP, p75, and pan-cadherin. Moreover, Aβ42 treatment dysregulated cellular homeostasis, as shown by the induction of p75-dependent neuronal death in two distinct cellular systems. Our findings raise the possibility that pathological elevations in Aβ42 contribute to cellular toxicity via the γ-secretase inhibition, and provide a novel conceptual framework to address Aβ toxicity in the context of γ-secretase-dependent homeostatic signaling.

PIP3-dependent Rac exchanger 1 (P-Rex1) is abundantly expressed in neutrophils and plays central roles in chemotaxis and cancer metastasis by serving as a guanine-nucleotide exchange factor (GEF) for Rac. The enzyme is synergistically activated by PIP3 and heterotrimeric Gβγ subunits, but mechanistic details remain poorly understood. While investigating the regulation of P-Rex1 by PIP3, we discovered that Ins(1,3,4,5)P4 (IP4) inhibits P-Rex1 activity and induces large decreases in backbone dynamics in diverse regions of the protein. Cryo-electron microscopy analysis of the P-Rex1·IP4 complex revealed a conformation wherein the pleckstrin homology (PH) domain occludes the active site of the Dbl homology (DH) domain. This configuration is stabilized by interactions between the first DEP domain (DEP1) and the DH domain and between the PH domain and a 4-helix bundle (4HB) subdomain that extends from the C-terminal domain of P-Rex1. Disruption of the DH-DEP1 interface in a DH/PH-DEP1 fragment enhanced activity and led to a more extended conformation in solution, whereas mutations that constrain the occluded conformation led to decreased GEF activity. Variants of full-length P-Rex1 in which the DH-DEP1 and PH-4HB interfaces were disturbed exhibited enhanced activity during chemokine-induced cell migration, confirming that the observed structure represents the autoinhibited state in living cells. Interactions with PIP3-containing liposomes led to disruption of these interfaces and increased dynamics protein-wide. Our results further suggest that inositol phosphates such as IP4 help to inhibit basal P-Rex1 activity in neutrophils, similar to their inhibitory effects on phosphatidylinositol-3-kinase.

Chitin is an abundant biopolymer and pathogen-associated molecular pattern that stimulates a host innate immune response. Mammals express chitin-binding and chitin-degrading proteins to remove chitin from the body. One of these proteins, Acidic Mammalian Chitinase (AMCase), is an enzyme known for its ability to function under acidic conditions in the stomach but is also active in tissues with more neutral pHs, such as the lung. Here, we used a combination of biochemical, structural, and computational modeling approaches to examine how the mouse homolog (mAMCase) can act in both acidic and neutral environments. We measured kinetic properties of mAMCase activity across a broad pH range, quantifying its unusual dual activity optima at pH 2 and 7. We also solved high-resolution crystal structures of mAMCase in complex with oligomeric GlcNAcn, the building block of chitin, where we identified extensive conformational ligand heterogeneity. Leveraging these data, we conducted molecular dynamics simulations that suggest how a key catalytic residue could be protonated via distinct mechanisms in each of the two environmental pH ranges. These results integrate structural, biochemical, and computational approaches to deliver a more complete understanding of the catalytic mechanism governing mAMCase activity at different pH. Engineering proteins with tunable pH optima may provide new opportunities to develop improved enzyme variants, including AMCase, for therapeutic purposes in chitin degradation.

Supramolecular chemistry focuses on the study of species joined by non-covalent interactions, and therefore on dynamic and relatively ill-defined structures. Despite being a well-developed field, it has to face important challenges when dealing with the selective recognition of biomolecules in highly competitive biomimetic media. However, supramolecular interactions reside at the core of chemical biology systems, since many processes in nature are governed by weak, non-covalent, strongly dynamic contacts. Therefore, there is a natural connection between these two research fields, which are not frequently related or share interests. In this feature article, I will highlight our most recent results in the molecular recognition of biologically relevant species, following different conceptual approaches from the most conventional design of elaborated receptors to the less popular dynamic combinatorial chemistry methodology. Selected illustrative examples from other groups will be also included. The discussion has been focused mainly on systems with potential biomedical applications. [ABSTRACT FROM AUTHOR]

Multi-functional cysteine-targeting covalent warheads possess significant therapeutic potential in medicinal chemistry and chemical biology. Herein, we present novel unsaturated and asymmetric ketone (oxazolinosene) scaffolds that selectively conjugate cysteine residues of peptides and bovine serum albumin under normal physiological conditions. This unsaturated saccharide depletes GSH in NCI-H1299 cells, leading to anti-tumor effects in vitro. The acetyl group of the ketal moiety on the saccharide ring can be converted to other carboxylic acids in a one-pot synthesis. In this way, the loaded acid can be click-released during cysteine conjugation, making the oxazolinosene a potential multifunctional therapeutic agent. The reaction kinetic model for oxazolinosene conjugation to GSH is well established and was used to evaluate oxazolinosene reactivity. The aforementioned oxazolinosenes were stereoselectively synthesized via a one-step reaction of nitriles with saccharides and conveniently converted into a series of α, β-unsaturated ketone N-glycosides as prevalent synthetic building blocks. The reaction mechanisms of oxazolinosene synthesis were investigated through calculations and validated with control experiments. Overall, these oxazolinosenes can be easily synthesized and developed as cysteine-targeted covalent warheads carrying useful click-releasing groups. Multifunctional cysteine targeting covalent warheads possess significant therapeutic potential in medicinal chemistry and chemical biology. Here, the authors develop an oxazolinosene scaffold from nitrile groups and saccharides that can selectively conjugate cysteine residues within peptides and proteins under physiological conditions, as well as deplete glutathione in cancer cells. [ABSTRACT FROM AUTHOR]

Sulfonyl fluorides hold significant importance as highly valued intermediates in chemical biology due to their optimal balance of biocompatibility with both aqueous stability and protein reactivity. The Cornella group introduced a one‐pot strategy for synthesizing aryl sulfonyl fluorides via Bi(III) redox‐neutral catalysis, which facilitates the transmetallation and direct insertion of SO2 into the BiC(sp2) bond giving the aryl sulfonyl fluorides. We report herein a comprehensive computational investigation of the redox‐neutral Bi(III) catalytic mechanism, disclose the critical role of the Bi(III) catalyst and base (i.e., K3PO4), and uncover the origin of SO2 insertion into the Bi(III)C(sp2) bond. The entire catalysis can be characterized via three stages: (i) transmetallation generating the Bi(III)‐phenyl intermediate IM3 facilitated by K3PO4. (ii) SO2 insertion into IM3 leading to the formation of Bi(III)‐OSOAr intermediate IM5. (iii) IM5 undergoes S(IV)‐oxidation yielding the aryl sulfonyl fluoride product 4 and liberating the Bi(III) catalyst for the next catalytic cycle. Each stage is kinetically and thermodynamically feasible. Moreover, we explored other some small molecules (NO2, CO2, H2O, N2O, etc.) insertion reactions mediated by the Bi(III)‐complex, and found that NO2 insertions could be easily achieved due to the low insertion barriers (i.e., 17.5 kcal/mol). Based on the detailed mechanistic study, we further rationally designed additional Bi(III) and Sb(III) catalysts, and found that some of which exhibit promising potential for experimental realization due to their low barriers (<16.4 kcal/mol). In this regard, our study contributes significantly to enhancing current Bi(III)‐catalytic systems and paving the way for novel Bi(III)‐catalyzed aryl sulfonyl fluoride formation reactions. [ABSTRACT FROM AUTHOR]

Recently, the introduction of fluorosulfonyl (−SO2F) groups have attracted considerable research interests, as this moiety could often afford enhanced activities and new functions in the context of chemical biology and drug discovery. Herein, we report the design and synthesis of 1‐fluorosulfamoyl‐pyridinium (FSAP) salts, which could serve as an effective photoredox‐active precursor to fluorosulfamoyl radicals and enable the direct radical C−H fluorosulfonamidation of a variety of (hetero)arenes. This method features mild conditions, visible light, broad substrate scope, good group tolerance, etc. and a metal‐free protocol is also viable by using organic photocatalysts. Further, FSAP can also be applied to the radical functionalization of alkenes via 1,2‐difunctionalization, radical distal migration, tandem radical‐polar crossover reactions, etc. In addition, a formal C−H methylamination of (hetero)arenes by combining this radical C−H fluorosulfonamidation with subsequent hydrolysis as well as product derivatization are also demonstrated. [ABSTRACT FROM AUTHOR]

Nitrile‐aminothiol conjugation (NATC) stands out as a promising biocompatible ligation technique due to its high chemo‐selectivity. Herein we investigated the reactivity and substrate scope of NAT conjugation chemistry, thus developing a novel pH dependent orthogonal NATC as a valuable tool for chemical biology. The study of reaction kinetics elucidated that the combination of heteroaromatic nitrile and aminothiol groups led to the formation of an optimal bioorthogonal pairing, which is pH dependent. This pairing system was effectively utilized for sequential and dual conjugation. Subsequently, these rapid (≈1 h) and high yield (>90 %) conjugation strategies were successfully applied to a broad range of complex biomolecules, including oligonucleotides, chelates, small molecules and peptides. The effectiveness of this conjugation chemistry was demonstrated by synthesizing a fluorescently labelled antimicrobial peptide‐oligonucleotide complex as a dual conjugate to imaging in live cells. This first‐of‐its‐kind sequential NATC approach unveils unprecedented opportunities in modern chemical biology, showcasing exceptional adaptability in rapidly creating structurally complex bioconjugates. Furthermore, the results highlight its potential for versatile applications across fundamental and translational biomedical research. [ABSTRACT FROM AUTHOR]

Hydrogen selenide (H2Se) is an emerging biomolecule of interest with similar properties to that of other gaseous signaling molecules (i.e., gasotransmitters that include nitric oxide, carbon monoxide, and hydrogen sulfide). H2Se is enzymatically generated in humans where it serves as a key metabolic intermediate in the production of selenoproteins and other selenium-containing biomolecules. However, beyond its participation in biosynthetic pathways, its involvement in cellular signaling or other biological mechanisms remains unclear. To uncover its true biological significance, H2Se-specific chemical tools capable of functioning under physiological conditions are required but lacking in comparison to those that exist for other gasotransmitters. Recently, researchers have begun to fill this unmet need by developing new H2Se-releasing compounds, along with pioneering methods for selenide detection and quantification. In combination, the chemical tools highlighted in this review have the potential to spark groundbreaking explorations into the chemical biology of H2Se, which may lead to its branding as the fourth official gasotransmitter. [ABSTRACT FROM AUTHOR]

Sulfur(VI)‐based functional groups are popular scaffolds in a wide variety of research fields including synthetic and medicinal chemistry, as well as chemical biology. The growing interest in sulfur(VI)‐containing molecules has motivated the scientific community to explore new methods to synthesize and modify them. Here, photocatalysis plays a key role granting access to new types of reactivity under mild reaction conditions. In this Perspective, we present a selection of works reported in the last six years focused on the photocatalytic assembly and reactivity of sulfones, sulfonamides, and sulfoximines. We addressed the key synthetic intermediates for each transformation, while discussing limitations and strength points of the protocols. Future directions of the field are finally presented. [ABSTRACT FROM AUTHOR]

Introduction: Ovarian and other peritoneal cancers have a strong tendency to metastasize into the surrounding adipose tissue. This study describes an effect of the adipose microenvironment on upregulation of sialic acid-containing glycans in ovarian cancer (OC). Heterogeneous populations of glycosylated OC tumors converged to a highly sialylated cell state that regulates tumorigenesis in an immune-dependent manner. Methods: We modeled the adipose microenvironment by conditioning growth media with human patient-derived adipose tissue. OC cell lines grown in the presence vs. absence of adipose conditioned media (ACM) were characterized by transcriptomics, western blotting, and chemical biology glycan labeling methods. Fluorescence-activated cell sorting was used to separate adipose-driven upregulation of hypersialylated ("SNA-high") vs. hyposialylated ("SNA-low") OC subpopulations. The two subpopulations were characterized by further transcriptomic and quantitative polymerase chain reaction analyses, then injected into a syngeneic mouse model. Immune system involvement was implicated using wild type and athymic nude mice with a primary endpoint of overall survival. Results: Adipose conditioning resulted in upregulation of sialyltransferases ST3GAL1, ST6GAL1, ST6GALNAC3, and ST8Sia1. In culture, OC cells displayed two distinct sialylated subpopulations that were stable for up to 9 passages, suggesting inherent heterogeneity in sialylation that is maintained throughout cell division and media changes. OC tumors that implanted in the omental adipose tissue exclusively reprogrammed to the highly sialylated subpopulation. In wild type C57BL/6 mice, only the hypersialylated SNA-high subpopulation implanted in the adipose, whereas the hyposialylated SNA-low subpopulation failed to be tumorigenic (p=0.023, n=5). In the single case where SNA-low established a tumor, post-mortem analysis revealed reprogramming of the tumor to the SNA-high state in vivo. In athymic nude mice, both subpopulations rapidly formed tumors, implicating a role of the adaptive immune system. Conclusions: These findings suggest a model of glycan-dependent tumor evolution wherein the adipose microenvironment reprograms OC to a tumorigenic state that resists the adaptive immune system. Mechanistically, adipose factors upregulate sialyltransferases. To our knowledge, this is the first demonstration of the effect of adipose microenvironment on OC tumor sialylation. Our results set the stage for translational applications targeting sialic acid pathways in OC and other peritoneal cancer tumorigenesis and metastasis. [ABSTRACT FROM AUTHOR]

Simple Summary: Human beings are always associated with small molecules throughout their lives. Chemical proteomics, which selectively identifies small-molecule targets, is an emerging approach for unraveling the mechanism of action of small molecules for therapeutic target identification and drug discovery. This review attempts to introduce representative techniques of chemical proteomics and summarizes examples of identifying small-molecule targets. Throughout the human lifespan, from conception to the end of life, small molecules have an intrinsic relationship with numerous physiological processes. The investigation into small-molecule targets holds significant implications for pharmacological discovery. The determination of the action sites of small molecules provide clarity into the pharmacodynamics and toxicological mechanisms of small-molecule drugs, assisting in the elucidation of drug off-target effects and resistance mechanisms. Consequently, innovative methods to study small-molecule targets have proliferated in recent years, with chemical proteomics standing out as a vanguard development in chemical biology in the post-genomic age. Chemical proteomics can non-selectively identify unknown targets of compounds within complex biological matrices, with both probe and non-probe modalities enabling effective target identification. This review attempts to summarize methods and illustrative examples of small-molecule target identification via chemical proteomics. It delves deeply into the interactions between small molecules and human biology to provide pivotal directions and strategies for the discovery and comprehension of novel pharmaceuticals, as well as to improve the evaluation of drug safety. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive experiment within the interdisciplinary field of chemical biology, closely aligned with the cutting-edge of the discipline, deeply integrating science and education. Utilizing both chemical and biological methods within an in vitro biochemical reaction system, this study investigates effects of the natural antioxidant quercetin on the redox cycle of myeloperoxidase (MPO) within biological organisms. The mechanism of quercetin affecting the chlorination activity of MPO is clarified through molecular docking techiniques and a series of UV-Vis absorption spectroscopy. The implementation of this experiment aids in broadening students’ perspectives, igniting their interest in scientific research, and enhancing their comprehensive experimental abilities. It offers valuable insights and examples for the development of multidisciplinary innovative talents in chemistry-related majors. [ABSTRACT FROM AUTHOR]

Iminosydnones (ImSyds) have renowned biological activities and attractive chemical properties for chemical biology. However, access to N6‐functionalized iminosydnones involves tricky and hazardous procedures. Thanks to an innovative mechanochemical strategy using 1,1'‐carbonyldiimidazole (CDI) as an activating agent, a straightforward synthesis of molsidomine and of a mesocarb analog, two bioactive iminosydnones, was achieved. The whole process, involving 4 linear steps, was carried out in the solid state by ball‐milling and with safe reagents, offering efficient and sustainable access to N‐carbonylated iminosydnones, in agreement with the principles of green chemistry. [ABSTRACT FROM AUTHOR]

Peptide nucleic acids (PNAs) combine the programmability of native nucleic acids with the robustness and ease of synthesis of a peptide backbone. These designer biomolecules have demonstrated tremendous utility across a broad range of applications, from the formation of bespoke biosupramolecular architectures to biosensing and gene regulation. Herein, we explore some of the key developments in the application of PNA in chemical biology and biotechnology in the last 5 years and present anticipated key areas of future development. [ABSTRACT FROM AUTHOR]

Investigating ligand-protein complexes is essential in the areas of chemical biology and drug discovery. However, detailed information on key reagents such as fluorescent tracers and associated data for the development of widely used bioluminescence resonance energy transfer (BRET) assays including NanoBRET, time-resolved Förster resonance energy transfer (TR-FRET) and fluorescence polarization (FP) assays are not easily accessible to the research community. We created tracerDB, a curated database of validated tracers. This resource provides an open access knowledge base and a unified system for tracer and assay validation. The database is freely available at https://www.tracerdb.org/. Tracers are fluorescent protein ligands required for various displacement assays. Here, the authors announce a curated database named tracerDB, which will make essential tracer data, contributed by the worldwide research community, easily available and searchable. [ABSTRACT FROM AUTHOR]

Fusion oncoproteins are associated with childhood cancers and have proven challenging to target, aside from those that include kinases. As part of its efforts for targeting childhood cancers, the National Cancer Institute recently conducted a series on Novel Chemical Approaches for Targeting Fusion Oncoproteins. Key learnings on leading platforms and technologies that can be used to advance the development of molecular therapeutics that target fusion oncoproteins in childhood cancers are described. Recent breakthroughs in medicinal chemistry and chemical biology provide new ground and creative strategies to exploit for the development of targeted agents for improving outcomes against these recalcitrant cancers. [ABSTRACT FROM AUTHOR]

Glucose and lipid metabolism are essential energy sources for the body. Dysregulation in these metabolic pathways is a significant risk factor for numerous acute and chronic diseases, including type 2 diabetes (T2DM), Alzheimer's disease (AD), obesity, and cancer. Post-translational modifications (PTMs), which regulate protein structure, localization, function, and activity, play a crucial role in managing cellular glucose and lipid metabolism. Among these PTMs, lysine methylation stands out as a key dynamic modification vital for the epigenetic regulation of gene transcription. Emerging evidence indicates that lysine methylation significantly impacts glucose and lipid metabolism by modifying key enzymes and proteins. This review summarizes the current understanding of lysine methylation's role and regulatory mechanisms in glucose and lipid metabolism. We highlight the involvement of methyltransferases (KMTs) and demethylases (KDMs) in generating abnormal methylation signals affecting these metabolic pathways. Additionally, we discuss the chemical biology and pharmacology of KMT and KDM inhibitors and targeted protein degraders, emphasizing their clinical implications for diseases such as diabetes, obesity, neurodegenerative disorders, and cancers. This review suggests that targeting lysine methylation in glucose and lipid metabolism could be an ideal therapeutic strategy for treating these diseases. [ABSTRACT FROM AUTHOR]

This article provides an overview of the field of bioorthogonal chemistry and its advancements at Radboud University. Bioorthogonal chemistry involves conducting chemical reactions within a biological environment with high selectivity and compatibility. Radboud University has made significant contributions to this field, including the development of strained alkynes and the synthesis of bioorthogonal tools such as BCN and TCO. These tools have been applied in various areas such as chemical biology and materials science. The article also highlights the interdisciplinary nature of research at Radboud University and the importance of synthetic availability in bioorthogonal reagents. The text specifically discusses the use of VBAs in bioorthogonal chemistry, particularly in the IEDDA reaction with tetrazines. The authors found that introducing boronic acid substituents on linear alkenes improved their reactivity in the IEDDA reaction. They also observed that the reactivity of VBAs varied depending on the coordinating substituent on the tetrazine. The authors explored the potential of VBAs in click-to-release chemistry, protein modification, and drug delivery applications. The article emphasizes the collaborative efforts and interdisciplinary approach necessary for advancing bioorthogonal chemistry. [Extracted from the article]

The text is an editorial from the International Journal of Molecular Sciences discussing the field of chemical biology. Chemical biology is an interdisciplinary field that combines chemistry, biology, and physics to study and manipulate biological systems using chemical techniques and compounds. The editorial highlights the history and development of chemical biology and its similarities to medicinal chemistry. It also mentions a special issue of the journal that covers various topics related to the discovery and investigation of bioactive compounds. The authors emphasize the importance of chemical biology in drug discovery and understanding diseases. [Extracted from the article]

The glucagon-like peptide-1 receptor (GLP-1R) is a class B G protein–coupled receptor involved in the regulation of blood glucose levels and food intake. Stabilized agonists targeting GLP-1R are used in the treatment of type 2 diabetes and have recently become a breakthrough obesity therapy. Here, we revisit a classic article in Diabetes by Thorens et al. that described the cloning, sequencing, and functional expression of the human GLP-1R. The article also demonstrated that exendin4(1-39) was a full agonist of the human GLP-1R whereas exendin4(9-39) was a full antagonist. We discuss how the knowledge imparted by these studies has gone on to inform multiple strands of GLP-1R biology over the past three decades, including pharmacology, signaling, human genetics, structural biology, and chemical biology. [ABSTRACT FROM AUTHOR]

The application of dyes to understanding the aetiology of infection inspired antimicrobial chemotherapy and the first wave of antibacterial drugs. The second wave of antibacterial drug discovery was driven by rapid discovery of natural products, now making up 69% of current antibacterial drugs. But now with the most prevalent natural products already discovered, ∼107 new soil-dwelling bacterial species must be screened to discover one new class of natural product. Therefore, instead of a third wave of antibacterial drug discovery, there is now a discovery bottleneck. Unlike natural products which are curated by billions of years of microbial antagonism, the vast synthetic chemical space still requires artificial curation through the therapeutics science of antibacterial drugs — a systematic understanding of how small molecules interact with bacterial physiology, effect desired phenotypes, and benefit the host. Bacterial molecular genetics can elucidate pathogen biology relevant to therapeutics development, but it can also be applied directly to understanding mechanisms and liabilities of new chemical agents with new mechanisms of action. Therefore, the next phase of antibacterial drug discovery could be enabled by integrating chemical expertise with systematic dissection of bacterial infection biology. Facing the ambitious endeavour to find new molecules from nature or new-to-nature which cure bacterial infections, the capabilities furnished by modern chemical biology and molecular genetics can be applied to prospecting for chemical modulators of new targets which circumvent prevalent resistance mechanisms. [ABSTRACT FROM AUTHOR]

Heterocyclics particularly those containing oxygen and nitrogen atoms are unique precursors for the synthesis of various agrochemicals and pharmaceuticals. Bis-coumarins are well-known oxygen-containing heterocycles of great significance. The development of methods to prepare bis-coumarins is of great interest in synthetic organic chemistry because of their versatile importance in medicinal chemistry and chemical biology. Bis-coumarins are well known for their antibiotic, antimicrobial, anti-HIV, and antitumor activity. Due to the vast application of bis-coumarins, the synthesis of these heterocycles has attracted huge interest from researchers. In this review, we have summarized the diverse synthetic routes of bis-coumarin synthesis making use of different catalysts and solvents under versatile reaction conditions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ambrosia grayi is a perennial weed native to northern Mexico, which can also be found in the Great Plains of the US. Outside the Americas, A. grayi has only been documented in Israel, where it is currently categorized as a casual species at advanced eradication stages. Here, we studied the plant biology and chemical weed management options of A. grayi. RESULTS: Only large achenes of A. grayi (~5% of all achenes) contain seeds; moreover, the viability of seeds extracted from large achenes was ~25%. Examination of plant anatomy revealed that underground vegetative segments show an anatomical structure of stems (rhizomes) with anomalous secondary growth. The optimal (night/day) temperature for the emergence of A. grayi rhizomes was 20/30 °C, and the emergence rate increased under elevated temperatures. Emergence may occur at different soil moisture content (25–60%); rhizomes were able to emerge even after 1 month of drought conditions (20%, 25% and 30%). Herbicide combinations, such as fluroxypyr + glufosinate, fluroxypyr + glyphosate, and glyphosate + saflufenacil + surfactant, were tested under quarantine conditions and showed high efficacy for the control of A. grayi. However, the efficiency of these treatments was highly correlated with plant growth stage. CONCLUSION: In Israel, the spread of A. grayi occurs mainly via rhizomes that can emerge under a wide range of temperatures and soil moisture conditions. Data regarding herbicide efficacy will aid in improving the eradication efforts taken by Israel's Plant Protection and Inspection Services. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

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Antibodies are critical reagents to detect and characterize proteins. It is commonly understood that many commercial antibodies do not recognize their intended targets, but information on the scope of the problem remains largely anecdotal, and as such, feasibility of the goal of at least one potent and specific antibody targeting each protein in a proteome cannot be assessed. Focusing on antibodies for human proteins, we have scaled a standardized characterization approach using parental and knockout cell lines (Laflamme et al., 2019) to assess the performance of 614 commercial antibodies for 65 neuroscience-related proteins. Side-by-side comparisons of all antibodies against each target, obtained from multiple commercial partners, have demonstrated that: (i) more than 50% of all antibodies failed in one or more applications, (ii) yet, ~50-75% of the protein set was covered by at least one high-performing antibody, depending on application, suggesting that coverage of human proteins by commercial antibodies is significant; and (iii) recombinant antibodies performed better than monoclonal or polyclonal antibodies. The hundreds of underperforming antibodies identified in this study were found to have been used in a large number of published articles, which should raise alarm. Encouragingly, more than half of the underperforming commercial antibodies were reassessed by the manufacturers, and many had alterations to their recommended usage or were removed from the market. This first study helps demonstrate the scale of the antibody specificity problem but also suggests an efficient strategy toward achieving coverage of the human proteome; mine the existing commercial antibody repertoire, and use the data to focus new renewable antibody generation efforts.

We have devised a single pot, low-cost method to add azide groups to unmodified nucleic acids without the need for enzymes or chemically modified nucleoside triphosphates. This involves reacting an azide-containing sulfinate salt with the nucleic acid, leading to replacement of C-H bonds on the nucleobase aromatic rings with C-R, where R is the azide-containing linker derived from the original sulfinate salt. With the addition of azide functional groups, the modified nucleic acid can easily be reacted with any alkyne-labeled compound of interest, including fluorescent dyes as shown in this work. This methodology enables the fluorescent labeling of a wide variety of nucleic acids, including natively folded RNAs, under mild conditions with minimal effects upon biochemical function and ribozyme catalysis. To demonstrate this, we show that a pair of labeled complementary ssDNA oligonucleotides (oligos) can hybridize to form dsDNA, even when labeled with multiple fluorophores per oligo. In addition, we also demonstrate that two different group II introns can splice when prelabeled internally with fluorophores, using our method. Broadly, this demonstrates that sulfinate modification of RNA is compatible with ribozyme function and Watson-Crick pairing, while preserving the labile backbone.

Target deconvolution is a crucial but costly and time-consuming task that hinders large-scale profiling for drug discovery. We present a matrix-augmented pooling strategy (MAPS) which mixes multiple drugs into samples with optimized permutation and delineates targets of each drug simultaneously with mathematical processing. We validated this strategy with thermal proteome profiling (TPP) testing of 15 drugs concurrently, increasing experimental throughput by 60x while maintaining high sensitivity and specificity. Benefiting from the lower cost and higher throughput of MAPS, we performed target deconvolution of the 15 drugs across 5 cell lines. Our profiling revealed that drug-target interactions can differ vastly in targets and binding affinity across cell lines. We further validated BRAF and CSNK2A2 as potential off-targets of bafetinib and abemaciclib, respectively. This work represents the largest thermal profiling of structurally diverse drugs across multiple cell lines to date.

[Display omitted] Molecular glues are typically small chemical molecules that act at the interface between a target protein and degradation machinery to trigger ternary complex formation. Identifying molecular glues is challenging. There is a scarcity of target-specific upregulating molecular glues, which are highly anticipated for numerous targets, including P53. P53 is degraded in proteasomes through polyubiquitination by specific E3 ligases, whereas deubiquitinases (DUBs) remove polyubiquitination conjugates to counteract these E3 ligases. Thus, small-molecular glues that enhance P53 anchoring to DUBs may stabilize P53 through deubiquitination. Here, using small-molecule microarray-based technology and unbiased screening, we identified three potential molecular glues that may tether P53 to the DUB, USP7, and elevate the P53 level. Among the molecular glues, bromocriptine (BC) is an FDA-approved drug with the most robust effects. BC was further verified to increase P53 stability via the predicted molecular glue mechanism engaging USP7. Consistent with P53 upregulation in cancer cells, BC was shown to inhibit the proliferation of cancer cells in vitro and suppress tumor growth in a xenograft model. In summary, we established a potential screening platform and identified potential molecular glues upregulating P53. Similar strategies could be applied to the identification of other types of molecular glues that may benefit drug discovery and chemical biology studies. [ABSTRACT FROM AUTHOR]

Introduction: Tetrandrine (Tet) is the main pharmacological component of Stephania tetrandra S. Moore, which is a well-documented traditional Chinese medicine known for its diuretic and antihypertensive properties. Unraveling the specific targets and mechanisms of Tet involved in inducing diuresis and mitigating hypertension can provide valuable insights into its therapeutic effects. This study aimed to explore the diuretic and antihypertensive targets and mechanisms of Tet using chemical biology coupled with activity analyses in vivo and in vitro. Methods: The diuretic effects of Tet were evaluated using a water-loaded mouse model. The direct target proteins for the diuretic and antihypertensive effects of Tet were determined using chemical biology. Furthermore, the molecular mechanism of Tet binding to target proteins was analyzed using a multidisciplinary approach based on the structure and function of the proteins. Finally, the effects of the Tet-targeted protein on downstream signaling pathways and blood pressure were evaluated in hypertensive model rats. Results: Tet exhibited significant antihypertensive and potassium-preserving diuretic effects. The mechanism underlying these effects involves the modulation of the enzyme activity by covalent binding of Tet to Cys423 of CYP11A1. This interaction alters the stability of heme within CYP11A1, subsequently impeding electron transfer and inhibiting aldosterone biosynthesis. Discussion: This study not only revealed the mechanism of the diuretic and antihypertensive effects of Tet but also discovered a novel covalent inhibitor of CYP11A1. These findings contribute significantly to our understanding of the therapeutic potential of Tet and provide a foundation for future research in the development of targeted treatments for hypertension. [ABSTRACT FROM AUTHOR]

Small molecule donors (SMDs) play subtle roles in the signaling mechanism and disease treatments. While many excellent SMDs have been developed, dosage control, targeted delivery, spatiotemporal feedback, as well as the efficiency evaluation of small molecules are still key challenges. Accordingly, fluorescent small molecule donors (FSMDs) have emerged to meet these challenges. FSMDs enable controllable release and non-invasive real-time monitoring, providing significant advantages for drug development and clinical diagnosis. Integration of FSMDs with chemotherapeutic, photodynamic or photothermal properties can take full advantage of each mode to enhance therapeutic efficacy. Given the remarkable properties and the thriving development of FSMDs, we believe a review is needed to summarize the design, triggering strategies and tracking mechanisms of FSMDs. With this review, we compiled FSMDs for most small molecules (nitric oxide, carbon monoxide, hydrogen sulfide, sulfur dioxide, reactive oxygen species and formaldehyde), and discuss recent progress concerning their molecular design, structural classification, mechanisms of generation, triggered release, structure–activity relationships, and the fluorescence response mechanism. Firstly, from the large number of fluorescent small molecular donors available, we have organized the common structures for producing different types of small molecules, providing a general strategy for the development of FSMDs. Secondly, we have classified FSMDs in terms of the respective donor types and fluorophore structures. Thirdly, we discuss the mechanisms and factors associated with the controlled release of small molecules and the regulation of the fluorescence responses, from which universal guidelines for optical properties and structure rearrangement were established, mainly involving light-controlled, enzyme-activated, reactive oxygen species-triggered, biothiol-triggered, single-electron reduction, click chemistry, and other triggering mechanisms. Fourthly, representative applications of FSMDs for trackable release, and evaluation monitoring, as well as for visible in vivo treatment are outlined, to illustrate the potential of FSMDs in drug screening and precision medicine. Finally, we discuss the opportunities and remaining challenges for the development of FSMDs for practical and clinical applications, which we anticipate will stimulate the attention of researchers in the diverse fields of chemistry, pharmacology, chemical biology and clinical chemistry. With this review, we hope to impart new understanding thereby enabling the rapid development of the next generation of FSMDs. [ABSTRACT FROM AUTHOR]

Cell mechanotransduction signals are important targets for physical therapy. However, current physiotherapy heavily relies on ultrasound, which is generated by high‐power equipment or amplified by auxiliary drugs, potentially causing undesired side effects. To address current limitations, a robotic actuation‐mediated therapy is developed that utilizes gentle mechanical loads to activate mechanosensitive ion channels. The resulting calcium influx precisely regulated the expression of recombinant tumor suppressor protein and death‐associated protein kinase, leading to programmed apoptosis of cancer cell line through caspase‐dependent pathway. In stark contrast to traditional gene therapy, the complete elimination of early‐ and middle‐stage tumors (volume ≤ 100 mm3) and significant growth inhibition of late‐stage tumor (500 mm3) are realized in tumor‐bearing mice by transfecting mechanogenetic circuits and treating daily with quantitative robotic actuation in a form of 5 min treatment over the course of 14 days. Thus, this massage‐derived therapy represents a quantitative strategy for cancer treatment. [ABSTRACT FROM AUTHOR]

Microproteins are a novel class of bioactive polypeptides that are encoded by small open reading frames (smORFs). Emerging evidence has demonstrated that these microproteins possess significant roles and undertake essential regulatory functions in living organisms. Meanwhile, several microproteins exhibit variable expression and distinct regulation in disease and healthy cells, revealing potential therapeutic interventions. A promising strategy to characterize microproteins and investigate their pathological association is through identification of microprotein‐protein interactions (MPIs), emphasizing the value of chemical biology tools for mapping MPIs. In this study, we applied twin‐strep tagging and TurboID proximity labeling strategies to unveil complicated cellular networks for microproteins. Encouraged by the success of both approaches in identifying the well‐studied CYREN‐Ku70/Ku80 complex, we investigated an uncharacterized FAM229B microprotein and found that it interacts with the thyroid receptor‐interacting protein 6 (TRIP6) and may regulate its nuclear translocation. Our study demonstrated that twin‐strep tagging and TurboID labeling strategies exhibited encouraging performance in identifying bona fide microprotein interacting partners. [ABSTRACT FROM AUTHOR]

The article discusses the cyanopyridine-aminthiol click reaction, a bioconjugation method that allows for precise and selective chemical modifications in complex biological systems. The reaction is efficient, exhibits excellent chemoselectivity, and is stable under mild redox conditions. It is orthogonal to most endogenous reactants, except for cysteine itself and peptides or proteins with N-terminal cysteine residues. The reaction has been used for peptide macrocyclization, the synthesis of macrocyclic peptides, and the creation of DNA-encoded libraries. Future research is needed to explore its potential for broader bioconjugation purposes. [Extracted from the article]

Sulfonyl fluorides have widespread applications in many fields, including organic synthesis, chemical biology, drug discovery and materials science. In particular, in the past decade, a number of aliphatic sulfonyl fluorides have been identified showing various biological activities. These applications and appealing features of sulfonyl fluorides have brought about a significant advancement in developing synthetic methods to access sulfonyl fluorides. In this review, we will discuss the recent developments of radical approaches for the synthesis of aliphatic sulfonyl fluorides. [ABSTRACT FROM AUTHOR]

Background: Trans-cyclooctenes (TCOs) are highly strained alkenes with remarkable reactivity towards tetrazines (Tzs) in inverse electron-demand Diels–Alder reactions. Since their discovery as bioorthogonal reaction partners, novel TCO derivatives have been developed to improve their reactivity, stability, and hydrophilicity, thus expanding their utility in diverse applications. Main body: TCOs have garnered significant interest for their applications in biomedical settings. In chemical biology, TCOs serve as tools for bioconjugation, enabling the precise labeling and manipulation of biomolecules. Moreover, their role in nuclear medicine is substantial, with TCOs employed in the radiolabeling of peptides and other biomolecules. This has led to their utilization in pretargeted nuclear imaging and therapy, where they function as both bioorthogonal tags and radiotracers, facilitating targeted disease diagnosis and treatment. Beyond these applications, TCOs have been used in targeted cancer therapy through a "click-to-release" approach, in which they act as key components to selectively deliver therapeutic agents to cancer cells, thereby enhancing treatment efficacy while minimizing off-target effects. However, the search for a suitable TCO scaffold with an appropriate balance between stability and reactivity remains a challenge. Conclusions: This review paper provides a comprehensive overview of the current state of knowledge regarding the synthesis of TCOs, and its challenges, and their development throughout the years. We describe their wide ranging applications as radiolabeled prosthetic groups for radiolabeling, as bioorthogonal tags for pretargeted imaging and therapy, and targeted drug delivery, with the aim of showcasing the versatility and potential of TCOs as valuable tools in advancing biomedical research and applications. [ABSTRACT FROM AUTHOR]

Peptide and protein postmodification have gained significant attention due to their extensive impact on biomolecule engineering and drug discovery, of which cysteine‐specific modification strategies are prominent due to their inherent nucleophilicity and low abundance. Herein, the study introduces a novel approach utilizing multifunctional 5‐substituted 1,2,3‐triazine derivatives to achieve multifaceted bioconjugation targeting cysteine‐containing peptides and proteins. On the one hand, this represents an inaugural instance of employing 1,2,3‐triazine in biomolecular‐specific modification within a physiological solution. On the other hand, as a powerful combination of precision modification and biorthogonality, this strategy allows for the one‐pot dual‐orthogonal functionalization of biomolecules utilizing the aldehyde group generated simultaneously. 1,2,3‐Triazine derivatives with diverse functional groups allow conjugation to peptides or proteins, while bi‐triazines enable peptide cyclization and dimerization. The examination of the stability of bi‐triazines revealed their potential for reversible peptide modification. This work establishes a comprehensive platform for identifying cysteine‐selective modifications, providing new avenues for peptide‐based drug development, protein bioconjugation, and chemical biology research. [ABSTRACT FROM AUTHOR]

The interaction between murine double minute 2 (MDM2) and p53, marked by transcriptional induction and feedback inhibition, orchestrates a functional loop dictating cellular fate. The functional loop comprising p53‐MDM2 axis is made up of an interactome consisting of approximately 81 proteins, which are spatio‐temporally regulated and involved in DNA repair mechanisms. Biochemical and genetic alterations of the interactome result in dysregulation of the p53‐mdm2 axis that leads to gastrointestinal (GI) cancers. A large subset of interactome is well known and it consists of proteins that either stabilize p53 or MDM2 and proteins that target the p53‐MDM2 complex for ubiquitin‐mediated destruction. Upstream signaling events brought about by growth factors and chemical messengers invoke a wide variety of posttranslational modifications in p53‐MDM2 axis. Biochemical changes in the transactivation domain of p53 impact the energy landscape, induce conformational switching, alter interaction potential and could change solubility of p53 to redefine its co‐localization, translocation and activity. A diverse set of chemical compounds mimic physiological effectors and simulate biochemical modifications of the p53‐MDM2 interactome. p53‐MDM2 interactome plays a crucial role in DNA damage and repair process. Genetic aberrations in the interactome, have resulted in cancers of GI tract (pancreas, liver, colorectal, gastric, biliary, and esophageal). We present in this article a review of the overall changes in the p53‐MDM2 interactors and the effectors that form an epicenter for the development of next‐generation molecules for understanding and targeting GI cancers. Significance Statement: This manuscript presents, a thorough analysis and dissection of p53‐MDM2 interactome, its regulation and genetic involvement in Cancers of GI tract. The manuscript also discusses about chemical biology of the p53 axis and how this can be translated to understand therapeutic aspects of the current understanding in cancer biology for cancer treatment. [ABSTRACT FROM AUTHOR]

With the advancement of multi-discipline studies, how to promote interdisciplinary research and to train graduate students with motivation and ability to perform chemistry-related interdisciplinary studies has become a topic of great interest for universities with chemistry departments. Based on the experiences of developing the interdisciplinary research field of chemical biology at Nanjing University, this article demonstrates a practical way to promote chemistry-related interdisciplinary research and graduate student training through the construction of well organized platforms such as the Chemistry and Biomedicine Innovation Center (ChemBIC) at Nanjing University [ABSTRACT FROM AUTHOR]

Inhibition of the bromodomain and extraterminal domain (BET) protein family is a potential strategy to prevent and treat diabetes; however, the clinical use of BET bromodomain inhibitors (BETis) is associated with adverse effects. Here, we explore a strategy for targeting BETis to b cells by exploiting the high-zinc (Zn2þ) concentration in b cells relative to other cell types. We report the synthesis of a novel, Zn2þ-chelating derivative of the pan-BETi (þ)-JQ1, (þ)-JQ1-DPA, in which (þ)-JQ1 was conjugated to dipicolyl amine (DPA). As controls, we synthesized (þ)-JQ1-DBA, a non-Zn2þ-chelating derivative, and (-)-JQ1-DPA, an inactive enantiomer that chelates Zn2þ. Molecular modeling and biophysical assays showed that (þ)-JQ1-DPA and (þ)-JQ1-DBA retain potent binding to BET bromodomains in vitro. Cellular assays demonstrated (þ)-JQ1-DPA attenuated NF-OEB target gene expression in b cells stimulated with the proinflammatory cytokine interleukin 1b. To assess b-cell selectivity, we isolated islets from a mouse model that expresses green fluorescent protein in insulin-positive b cells and mTomato in insulin-negative cells (non-b cells). Surprisingly, Zn2þ chelation did not confer b-cell selectivity as (þ)-JQ1-DPA was equally effective in both b and a cells; however, (þ)-JQ1-DPA was less effective in macrophages, a nonendocrine islet cell type. Intriguingly, the non-Zn2þ-chelating derivative (þ)-JQ1-DBA displayed the opposite selectivity, with greater effect in macrophages compared with (þ)-JQ1-DPA, suggesting potential as a macrophage-targeting molecule. These findings suggest that Zn2þ-chelating small molecules confer endocrine cell selectivity rather than b-cell selectivity in pancreatic islets and provide valuable insights and techniques to assess Zn2þ chelation as an approach to selectively target small molecules to pancreatic b cells. NEW & NOTEWORTHY Inhibition of BET bromodomains is a novel potential strategy to prevent and treat diabetes mellitus. However, BET inhibitors have negative side effects. We synthesized a BET inhibitor expected to exploit the high zinc concentration in b cells to accumulate in b cells. We show our inhibitor targeted pancreatic endocrine cells; however, it was less effective in immune cells. A control inhibitor showed the opposite effect. These findings help us understand how to target specific cells in diabetes treatment. [ABSTRACT FROM AUTHOR]

Covering: 1995 to 2023 Advances in bioanalytical methods, particularly mass spectrometry, have provided valuable molecular insights into the mechanisms of life. Non-targeted metabolomics aims to detect and (relatively) quantify all observable small molecules present in a biological system. By comparing small molecule abundances between different conditions or timepoints in a biological system, researchers can generate new hypotheses and begin to understand causes of observed phenotypes. Functional metabolomics aims to investigate the functional roles of metabolites at the scale of the metabolome. However, most functional metabolomics studies rely on indirect measurements and correlation analyses, which leads to ambiguity in the precise definition of functional metabolomics. In contrast, the field of natural products has a history of identifying the structures and bioactivities of primary and specialized metabolites. Here, we propose to expand and reframe functional metabolomics by integrating concepts from the fields of natural products and chemical biology. We highlight emerging functional metabolomics approaches that shift the focus from correlation to physical interactions, and we discuss how this allows researchers to uncover causal relationships between molecules and phenotypes. [ABSTRACT FROM AUTHOR]

Cellulose is an abundant component of plant cell wall matrices, and this para-crystalline polysaccharide is synthesized at the plasma membrane by motile Cellulose Synthase Complexes (CSCs). However, the factors that control CSC activity and motility are not fully resolved. In a targeted chemical screen, we identified the alkylated nojirimycin analog N -Dodecyl Deoxynojirimycin (ND-DNJ) as a small molecule that severely impacts Arabidopsis seedling growth. Previous work suggests that ND-DNJ-related compounds inhibit the biosynthesis of glucosylceramides (GlcCers), a class of glycosphingolipid associated with plant membranes. Our work uncovered major changes in the sphingolipidome of plants treated with ND-DNJ, including reductions in GlcCer abundance and altered acyl chain length distributions. Crystalline cellulose content was also reduced in ND-DNJ-treated plants as well as plants treated with the known GlcCer biosynthesis inhibitor N-[2-hydroxy-1-(4-morpholinylmethyl)-2-phenyl ethyl]-decanamide (PDMP) or plants containing a genetic disruption in GLUCOSYLCERAMIDE SYNTHASE (GCS), the enzyme responsible for sphingolipid glucosylation that results in GlcCer synthesis. Live-cell imaging revealed that CSC speed distributions were reduced upon treatment with ND-DNJ or PDMP, further suggesting an important relationship between glycosylated sphingolipid composition and CSC motility across the plasma membrane. These results indicate that multiple interventions compromising GlcCer biosynthesis disrupt cellulose deposition and CSC motility, suggesting that GlcCers regulate cellulose biosynthesis in plants. [ABSTRACT FROM AUTHOR]

Aryl diazonium intermediates have emerged as highly versatile intermediates in modern organic synthesis and chemical biology, demonstrating remarkable reactivity under mild reaction conditions. Their significance has extended to DNA‐encoded libraries (DELs), where they serve as valuable alternatives to traditional aryl halide‐based cross‐coupling reactions. Aryl diazonium intermediates as N2‐annulation synthons can efficiently transform into benzotriazinone core on DNA besides C−C coupling. This concept paper illuminates recent advances in this field, emphasizing their applications and potential across various facets of DELs, off‐DNA chemistry, DELs selection, and DNA‐based probes. It is anticipated that these developments will propel the broader utilization of DNA‐conjugated aryl diazonium salt intermediates in DELs, protein labeling, hit discovery, and other interdisciplinary fields. [ABSTRACT FROM AUTHOR]

Multicellular organisms are composed of many tissue types that have distinct morphologies and functions, which are largely driven by specialized proteomes and interactomes. To define the proteome and interactome of a specific type of tissue in an intact animal, we developed a localized proteomics approach called Methionine Analog-based Cell-Specific Proteomics and Interactomics (MACSPI). This method uses the tissue-specific expression of an engineered methionyl-tRNA synthetase to label proteins with a bifunctional amino acid 2-amino-5-diazirinylnonynoic acid in selected cells. We applied MACSPI in Caenorhabditis elegans, a model multicellular organism, to selectively label, capture, and profile the proteomes of the body wall muscle and the nervous system, which led to the identification of tissue-specific proteins. Using the photo-cross-linker, we successfully profiled HSP90 interactors in muscles and neurons and identified tissue-specific interactors and stress-related interactors. Our study demonstrates that MACSPI can be used to profile tissue-specific proteomes and interactomes in intact multicellular organisms. [ABSTRACT FROM AUTHOR]

The most common malignancy in women is breast cancer. During the development of cancer, oncogenic transcription factors facilitate the overproduction of inflammatory cytokines and cell adhesion molecules. Antiapoptotic proteins are markedly upregulated in cancer cells, which promotes tumor development, metastasis, and cell survival. Promising findings have been found in studies on the cell cycle-mediated apoptosis pathway for medication development and treatment. Dietary phytoconstituents have been studied in great detail for their potential to prevent cancer by triggering the body's defense mechanisms. The underlying mechanisms of action may be clarified by considering the role of polyphenols in important cancer signaling pathways. Phenolic acids, flavonoids, tannins, coumarins, lignans, lignins, naphthoquinones, anthraquinones, xanthones, and stilbenes are examples of natural chemicals that are being studied for potential anticancer drugs. These substances are also vital for signaling pathways. This review focuses on innovations in the study of polyphenol genistein's effects on breast cancer cells and presents integrated chemical biology methods to harness mechanisms of action for important therapeutic advances. [ABSTRACT FROM AUTHOR]

Partial charges are a central concept in general chemistry and chemical biology, yet dozens of different computational definitions exist. In prior work [Cho et al., ChemPhysChem21, 688‐696 (2020)], we showed that these can be reduced to at most three 'principal components of ionicity'. The present study addressed the dependence of computed partial charges q on 1‐particle basis set and (for WFT methods) n‐particle correlation treatment or (for DFT methods) exchange‐correlation functional, for several representative partial charge definitions such as QTAIM, Hirshfeld, Hirshfeld‐I, HLY (electrostatic), NPA, and GAPT. Our findings show that semi‐empirical double hybrids can closely approach the CCSD(T) 'gold standard' for this property. In fact, owing to an error compensation in MP2, CCSD partial charges are further away from CCSD(T) than is MP2. The nonlocal correlation is important, especially when there is a substantial amount of nonlocal exchange. Employing range separation proves to be "mostly" not advantageous, while global hybrids perform optimally for 20%–30% Hartree‐Fock exchange across all charge types. Basis set convergence analysis shows that an augmented triple‐zeta heavy‐aug‐cc‐pV(T+d)Z basis set or a partially augmented jun‐cc‐pV(T+d)Z basis set is sufficient for Hirshfeld, Hirshfeld‐I, HLY, and GAPT charges. In contrast, QTAIM and NPA display slower basis set convergence. It is noteworthy that for both NPA and QTAIM, HF exhibits markedly slower basis set convergence than the correlation components of MP2 and CCSD. Triples corrections in CCSD(T), denoted as CCSD(T)‐CCSD, exhibit even faster basis set convergence. [ABSTRACT FROM AUTHOR]

This paper presents an efficient and practical protocol for the synthesis of rufinamide (anti-epileptic drugs) active pharmaceutical ingredient (API) and several process impurities by a 1,3-dipolar cycloaddition reaction, starting from commercially available benzyl bromides. The earlier reported syntheses of rufinamide had encountered challenges in isolating by-products from the mother liquor. In this work, the impurities were synthesized via the retrosynthesis route to serve as reference samples for assessing the purity level of drugs. These impurities, characterized by the presence of N-group and azole derivatives, find wide-range applications in academic and industrial settings, including organic synthesis, drug discovery, polymer chemistry, chemical biology, and supramolecular chemistry. The primary objective of this synthesis was to propose a reliable and pragmatic method for producing rufinamide and its impurities to address diverse scientific and industrial requirements. The protocol outlined in this research aims to contribute to the development of robust methodologies for the synthesis of pharmaceuticals and associated impurities, with potential implications for drug development and chemical research. [ABSTRACT FROM AUTHOR]

BACKGROUND: Background: Neurodegenerative diseases manifest behavioral dysfunction with disease progression. Intervention with neuropsychiatric drugs is part of most multi-drug treatment paradigms. However, only a fraction of patients responds to the treatments and those responding must deal with drug-drug interactions and tolerance issues generally attributed to off-target activities. Recent efforts have focused on the identification of underexplored targets and exploration of improved outcomes by treatment with selective molecular probes. Objective: As part of ongoing efforts to identify and validate additional targets amenable to therapeutic intervention, we examined levels of the serotonin 5-HT2b receptor (5-HT2bR) in Alzheimer's disease (AD) brains and the potential of a selective 5-HT2bR antagonist to counteract synaptic plasticity and memory damage induced by AD-related proteins, amyloid-β, and tau. Methods: This work used a combination of biochemical, chemical biology, electrophysiological, and behavioral techniques. Biochemical methods included analysis of protein levels. Chemical biology methods included the use of an in vivo molecular probe MW071, a selective antagonist for the 5HT2bR. Electrophysiological methods included assessment of long-term potentiation (LTP), a type of synaptic plasticity thought to underlie memory formation. Behavioral studies investigated spatial memory and associative memory. Results: 5HT2bR levels are increased in brain specimens of AD patients compared to controls. 5HT2bR antagonist treatment rescued amyloid-β and tau oligomer-induced impairment of synaptic plasticity and memory. Conclusions: The increased levels of 5HT-2bR in AD patient brains and the attenuation of disease-related synaptic and behavioral dysfunctions by MW071 treatment suggest that the 5HT-2bR is a molecular target worth pursuing as a potential therapeutic target. [ABSTRACT FROM AUTHOR]