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The modulation of protein-protein interactions with small molecules is one of the most rapidly developing areas in drug discovery. In this review, we discuss advances over the past decade (2014-2023) focusing on molecular glues (MGs)-monovalent small molecules that induce proximity, either by stabilizing native interactions or by inducing neomorphic interactions. We include both serendipitous and rational discoveries and describe the different approaches that were used to identify them. We classify the compounds in three main categories: degradative MGs, non-degradative MGs or PPI stabilizers, and MGs that induce self-association. Diverse, illustrative examples with structural data are described in detail, emphasizing the elements of molecular recognition and cooperative binding at the interface that are fundamental for a MG mechanism of action.

Pioneer transcription factors (TFs) bind to and open closed chromatin, facilitating engagement by other regulatory factors involved in gene activation or repression. Chemical probes are lacking for pioneer TFs, which has hindered their mechanistic investigation in cells. Here, we report the chemical proteomic discovery of electrophilic compounds that stereoselectively and site-specifically bind the pioneer TF forkhead box protein A1 (FOXA1) at a cysteine (C258) within the forkhead DNA-binding domain. We show that these covalent ligands react with FOXA1 in a DNA-dependent manner and rapidly remodel its pioneer activity in prostate cancer cells reflected in redistribution of FOXA1 binding across the genome and directionally correlated changes in chromatin accessibility. Motif analysis supports a mechanism where the ligands relax the canonical DNA-binding preference of FOXA1 by strengthening interactions with suboptimal sequences in predicted proximity to C258. Our findings reveal a striking plasticity underpinning the pioneering function of FOXA1 that can be controlled by small molecules. [Display omitted] • Activity-based protein profiling identifies covalent ligands for FOXA1 • Covalent ligands react with cysteine-258 of FOXA1 in a DNA-dependent manner • Covalent ligands remodel the pioneering activity of FOXA1 in prostate cancer cells • Covalent ligands relax the canonical DNA-binding preferences of FOXA1 Won et al. present the chemical proteomic discovery of covalent small molecules that stereoselectively and site-specifically engage the pioneer transcription factor FOXA1. These compounds rapidly remodel FOXA1 interactions with chromatin in prostate cancer cells and create corresponding changes in chromatin accessibility through relaxing the DNA-binding preferences of FOXA1. [ABSTRACT FROM AUTHOR]

Phosphorus shows promise as a next‐generation anode material due to its high theoretical capacity of 2596 mAh g−1. However, challenges such as low conductivity, severe volume expansion, and the dissolution and migration of electrolyte‐soluble lithium polyphosphides hamper high‐performance capabilities. While carbon composites are widely researched as a solution through the physical encapsulation of micro‐nano‐phosphorus domains, anodes still exhibit low cycling stability and rate performance. In response, this work proposes a new approach, focusing on chemical anchoring and molecular dispersion of phosphorus within the carbon host. Through laser irradiation of a red phosphorus/phenolic resin blend, in‐situ covalent binding of molecular phosphorus adducts to the as‐forming laser‐induced graphene is observed; directly synthesizing an additive‐free, flexible and 3‐dimensional mesoporous composite anode with high phosphorus content (33 wt.%), specific surface area (163.4 m2 g−1) and intrinsic conductivity (12 S cm−1). These anodes demonstrate remarkable cycling stability, with capacity retention of 98% after 3000 cycles at a high current density of 2 A g−1 and capacity of 673 mAh g−1. The high cycling stability is further confirmed through the complete inhibition of lithium polyphosphide "shuttle effect" by chemical anchoring of the molecularly dispersed active material. Furthermore, scale‐up prospects utilizing laser‐assisted additive manufacturing are investigated. [ABSTRACT FROM AUTHOR]

BACKGROUND: Wheat proteins can be divided into water/salt‐soluble protein (albumin/globulin) and water/salt‐insoluble protein (gliadins and glutenins (Glu)) according to solubility. Gliadins (Glia) are one of the major allergens in wheat. The inhibition of Glia antigenicity by conventional processing techniques was not satisfactory. RESULTS: In this study, free radical oxidation was used to induce covalent reactions. The effects of covalent reactions by high‐intensity ultrasound (HIU) of different powers was compared. The enhancement of covalent grafting effectiveness between gliadin and (−)‐epigallo‐catechin 3‐gallate (EGCG) was confirmed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis, matrix‐assisted laser desorption/ionization–time‐of‐flight–mass spectrometry and Folin–Ciocalteu tests. HIU caused protein deconvolution and disrupted the intrastrand disulfide bonds that maintain the tertiary structure, causing a shift in the side chain structure, as proved by Fourier, fluorescence and Raman spectroscopic analysis. Comparatively, the antigenic response of the conjugates formed in the sonication environment was significantly weaker, while these conjugates were more readily hydrolyzed and less antigenic during simulated gastrointestinal fluid digestion. CONCLUSION: HIU‐enhanced free radical oxidation caused further transformation of the spatial structure of Glia, which hid or destroyed the antigenic epitope, effectively inhibiting protein antigenicity. This study widened the application of polyphenol modification in the inhibition of wheat allergens. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Isotonitazene belongs to a potent class of μ‐opioid receptor (μOR) ligands, known as nitazenes. The lack of knowledge surrounding this agonist and others in its class has sparked thorough re‐investigations. To aid in these investigations, the purportedly covalent yet underexplored nitazene BIT was biochemically re‐evaluated in this work, along with a newly synthesized analogue, Iso‐BIT. Moreover, in the pursuit of understanding the mechanism, function and interactions of the μOR, this study involved developing photoswitchable nitazene derivatives as potential probe molecules. Converting known ligands into azo‐containing photoswitchable derivatives offers the opportunity to modulate ligand structure with light, allowing for photocontrol of compound activity. While photocontrol of μOR activity could not be entirely achieved, photophysical evaluation of these 2‐benzimidazole azo‐arenes revealed a novel photoswitch scaffold that responds to visible light. Furthermore, azo‐containing 2 e and 3 e emerged as promising nitazene derivatives that were able to form an exceptionally high fraction of covalent‐ligand receptor complexes with wild‐type μOR at physiological pH. [ABSTRACT FROM AUTHOR]

Extant enzymes with precisely arranged multiple residues in their three‐dimensional binding pockets are capable of exhibiting remarkable stereoselectivity towards a racemic mixture of substrates. However, how early protein folds that possibly featured short peptide fragments facilitated enantioselective catalytic transformations important for the emergence of homochirality still remains an intriguing open question. Herein, enantioselective hydrolysis was shown by short peptide‐based nanotubes that could exploit multiple solvent‐exposed residues to create chiral binding grooves to covalently interact and subsequently hydrolyse one enantiomer preferentially from a racemic pool. Single or double‐site chiral mutations led to opposite but diminished and even complete loss of enantioselectivities, suggesting the critical roles of the binding enthalpies from the precise localization of the active site residues, despite the short sequence lengths. This work underpins the enantioselective catalytic prowess of short peptide‐based folds and argues their possible role in the emergence of homochiral chemical inventory. [ABSTRACT FROM AUTHOR]

Achieving a planar hypercoordinate arrangement of s‐block metals through covalent bonding with ligands is challenging due to the strong ionicity involved. Herein, we report the first case of a neutral binary global minimum containing a planar hexacoordinate beryllium atom. The central Be atom is coordinated by six active Be atoms, the latter in turn are enclosed by an equal number of more electronegative chlorine atoms in the periphery, forming a star‐like phBe cluster (Be©Be6Cl6). Importantly, the cluster exhibits dynamically stabilized stemming geometrically from the appropriate matching of metal‐ligand size and electronically from adherence to the octet rule as well as possessing a 6σ/2π double aromaticity. Remarkably, energy decomposition analysis‐natural orbitals for chemical valence (EDA‐NOCV) analysis reveals a significant covalent interaction between the ligand and the central metal beryllium atoms, a fact further supported by a large Wiberg bond index. This cluster is a promising synthetic as its excellent electronic, dynamic and thermodynamic stability. [ABSTRACT FROM AUTHOR]

Covalent hits for drug discovery campaigns are neither fantastic beasts nor mythical creatures, they can be routinely identified through electrophile-first screening campaigns using a suite of different techniques. These include biophysical and biochemical methods, cellular approaches, and DNA-encoded libraries. Employing best practice, however, is critical to success. The purpose of this review is to look at state of the art covalent hit identification, how to identify hits from a covalent library and how to select compounds for medicinal chemistry programmes.

The TRPA1 ion channel is activated by electrophilic compounds through the covalent modification of intracellular cysteine residues. How non-covalent agonists activate the channel and whether covalent and non-covalent agonists elicit the same physiological responses are not understood. Here, we report the discovery of a non-covalent agonist, GNE551, and determine a cryo-EM structure of the TRPA1-GNE551 complex, revealing a distinct binding pocket and ligand-interaction mechanism. Unlike the covalent agonist allyl isothiocyanate, which elicits channel desensitization, tachyphylaxis, and transient pain, GNE551 activates TRPA1 into a distinct conducting state without desensitization and induces persistent pain. Furthermore, GNE551-evoked pain is relatively insensitive to antagonist treatment. Thus, we demonstrate the biased agonism of TRPA1, a finding that has important implications for the discovery of effective drugs tailored to different disease etiologies.

Through metal doping, boron clusters can exhibit special structural features and chemical properties. Although boron clusters doped with main group metals, transition metals and lanthanide metals have been reported previously, there are relatively few studies on boron clusters doped with actinide metals. In this work, a series of actinide metal-doped boron clusters AnB7(An=Ac, Th, Am, Cm) were predicted. Density functional theoretical calculations show that the global minima are C6vAcB7, C2vThB7, C2vAmB7 and C6vCmB7, and all are half-sandwich structures. In each AnB7 species, B3-7 has six delocalized π electrons and six delocalized σ electrons, all of which are double aromatic clusters. The analysis of bonding properties shows that the covalent interactions of Am-B and Cm-B bonds are stronger than those of Ac-B and Th-B bonds. In addition, these boron clusters are very stable, and AmB7 and CmB7 are more stable. Covalent interaction is an important factor affecting the stability of AnB7. This work enriches the types of boron clusters doped with actinide metal atoms, and provides a theoretical basis for the design of actinide metal doped boron cluster materials.

Although NPM1 mutations are frequently found in acute myeloid leukemia patients, therapeutic strategies are scarce and unsuitable for those who cannot tolerate intensive chemotherapy. Here we demonstrated that heliangin, a natural sesquiterpene lactone, exerts favorable therapeutic responses in NPM1 mutant acute myeloid leukemia cells, with no apparent toxicity to normal hematogenous cells, by inhibiting their proliferation, inducing apoptosis, causing cell cycle arrest, and promoting differentiation. In-depth studies on its mode of action using quantitative thiol reactivity platform screening and subsequent molecular biology validation showed that the ribosomal protein S2 (RPS2) is the main target of heliangin in treating NPM1 mutant AML. Upon covalent binding to the C222 site of RPS2, the electrophilic moieties of heliangin disrupt pre-rRNA metabolic processes, leading to nucleolar stress, which in turn regulates the ribosomal proteins–MDM2–p53 pathway and stabilizes p53. Clinical data shows that the pre-rRNA metabolic pathway is dysregulated in acute myeloid leukemia patients with the NPM1 mutation, leading to a poor prognosis. We found that RPS2 plays a critical role in regulating this pathway and may be a novel treatment target. Our findings suggest a novel treatment strategy and lead compound for acute myeloid leukemia patients, especially those with NPM1 mutations.

This review emphasized structure and features of high performance covalently linked polymer/fullerene nanocomposite. The polymer grafting on fullerene molecules may usually occur through covalent bonding. The covalently linked nanocomposites improved fullerene dispersion and matrix-nanofiller interactions. Fullerene molecules have been grafted to conducting polymers (polyaniline, polythiophene, polythiophene derivatives, etc.) and thermoplastic/thermosetting polymers/block copolymers. The covalent grafting of polymer chains on fullerene molecules may lead to exceptional structural, morphological, electrical, thermal, and other physical properties. Development of unique star-shape/dendritic polymer/fullerene assemblies was also observed. The covalently interconnected polymer/fullerene nanocomposite possess remarkable physical contour for high-tech applications including solar cells, optical sensors, supercapacitors, and biomedical fields. [ABSTRACT FROM AUTHOR]

The COVID‐19 pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), is still affecting people worldwide. Despite the good degree of immunological protection achieved through vaccination, there are still severe cases that require effective antivirals. In this sense, two specific pharmaceutical preparations have been marketed already, the RdRp polymerase inhibitor molnupiravir and the main viral protease inhibitor nirmatrelvir (commercialized as Paxlovid, a combination with ritonavir). Nirmatrelvir is a peptidomimetic acting as orally available, covalent, and reversible inhibitor of SARS‐CoV‐2 main viral protease. The success of this compound has revitalized the search for new peptide and peptidomimetic protease inhibitors. This highlight collects some selected examples among those recently published in the field of SARS‐CoV‐2. [ABSTRACT FROM AUTHOR]

Context: Just how much effort and detail should we invest in analyzing interactions of the order of 5 kcal mol−1? This comment attempts to provide a conciliatory overview of what is often a contentious field and to pose some questions that I hope will eventually lead at least to some consensus. Methods: This is an opinion article without calculations or data. [ABSTRACT FROM AUTHOR]

Abstract Cancer is one of the leading causes of death worldwide. The proliferation, survival, and metastasis of cancer cells are governed by a complex series of intracellular and extracellular signaling pathways. Therefore, efficient cancer therapy often requires the modulation of multiple targets. Besides, the modulation of several biological targets with a single drug can lead to synergistic therapeutic effects and avoid side effects associated with combination therapy. Oridonin, an ent‐kaurane type diterpenoid isolated from Rabdosia rubescens, has been reported to possess potent anti‐inflammatory, antioxidant, anticancer, and neuroprotective activities. Among its many benefits, the anticancer effects have attracted the most attention because of its effectiveness in many tumor cells and its potential to overcome therapeutic resistance. Recently, several proteins involved in oncogenic signaling, including CRM1, PHGDH, HSP70, AML1‐ETO, and STAT3, were identified as functional targets of oridonin and its analogs. The binding mechanism and the consequence of oridonin binding to these oncogenic proteins are summarized and discussed. These advances suggest that oridonin exhibits broad spectrum anticancer effects by targeting multiple oncogenic proteins mainly via Michael addition between its unsaturated ketone and the cysteines in the target proteins. Therefore, oridonin and its derivatives hold the potential to be developed as multitargeting anticancer drugs.

Although NPM1 mutations are frequently found in acute myeloid leukemia patients, therapeutic strategies are scarce and unsuitable for those who cannot tolerate intensive chemotherapy. Here we demonstrated that heliangin, a natural sesquiterpene lactone, exerts favorable therapeutic responses in NPM1 mutant acute myeloid leukemia cells, with no apparent toxicity to normal hematogenous cells, by inhibiting their proliferation, inducing apoptosis, causing cell cycle arrest, and promoting differentiation. In-depth studies on its mode of action using quantitative thiol reactivity platform screening and subsequent molecular biology validation showed that the ribosomal protein S2 (RPS2) is the main target of heliangin in treating NPM1 mutant AML. Upon covalent binding to the C222 site of RPS2, the electrophilic moieties of heliangin disrupt pre-rRNA metabolic processes, leading to nucleolar stress, which in turn regulates the ribosomal proteins–MDM2–p53 pathway and stabilizes p53. Clinical data shows that the pre-rRNA metabolic pathway is dysregulated in acute myeloid leukemia patients with the NPM1 mutation, leading to a poor prognosis. We found that RPS2 plays a critical role in regulating this pathway and may be a novel treatment target. Our findings suggest a novel treatment strategy and lead compound for acute myeloid leukemia patients, especially those with NPM1 mutations. By covalent targeting RPS2, HEL impairs pre-rRNA metabolic processes therefore stabilizes p53 in NPM1 -mutated AML cells. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper focuses on creating one-dimensional diffractive grooved structures of antigen proteins on glass substrates for the label-free detection of antibodies to dairy allergens. In particular, the fabrication of protein structures is carried out by combining microcontact printing with physisorption, imines coupling, and thiol-ene click chemistry. The work first sets up these patterning methods and discusses and compares the main aspects involved in them (structure, biolayer thickness, functionality, stability). Homogeneous periodic submicron structures of proteins are created and characterized by diffractive measurements, AFM, FESEM, and fluorescence scanning. Then, this patterning method is applied to proteins involved in cow milk allergy, and the resulting structures are implemented as optical transducers to sense specific immunoglobulins G. In particular, gratings of bovine serum albumin, casein, and β-lactoglobulin are created and assessed, reaching limits of detection in the range of 30–45 ng·mL−1 of unlabeled antibodies by diffractive biosensing. [ABSTRACT FROM AUTHOR]

The physical stability of protein-based emulsions depends on intra- and intermolecular interactions of the interfacial protein-film. As studied in aqueous systems before, phenolic acid derivatives (PADs) non-covalently or covalently crosslink proteins depending on pH-value and thus, may impact interfacial protein-films. Whether these interactions occur in the same manner at the interface as in water and how they vary the properties of the interfacial protein-film has not been clarified. The present study aimed to investigate the interfacial protein-film viscoelasticity and physical emulsion-stability after non-covalently (pH 6.0) and covalently (pH 9.0) crosslinking depending on PAD-structure. For this purpose, we studied an interfacial β-lactoglobulin film with dilatational rheology after crosslinking with PADs, varying in number of π-electrons and polar substituents. Then, we analyzed the physical emulsion-stability by visual evaluation and particle size distribution. The results indicate that PADs with a high number of π-electrons (rosmarinic acid and chicoric acid) weaken the protein-film due to competing of phenol-protein interactions with protein-protein interactions. This is reflected in a decrease in interfacial elasticity. PADs with an additional polar substituent (verbascoside and cynarine) seem to further weaken the protein film, since the affinity of the PADs to the interface increases, PADs preferentially adsorb and sterically hinder protein-protein interactions. In emulsions at pH 6.0 and thus low electrostatic repulsion, PADs promote bridging-flocculation. Due to higher electrostatic repulsion at pH 9.0, the PADs are sterically hindered to form bridges, even though they are polymeric. Hence, our research enables the control of protein-film viscoelasticity and emulsion-stability depending on the PAD-structure. [ABSTRACT FROM AUTHOR]

The NLRP3 inflammasome promotes inflammation in disease, yet the full repertoire of mechanisms regulating its activity is not well delineated. Among established regulatory mechanisms, covalent modification of NLRP3 has emerged as a common route for the pharmacological inactivation of this protein. Here, we show that inhibition of the glycolytic enzyme phosphoglycerate kinase 1 (PGK1) results in the accumulation of methylglyoxal, a reactive metabolite whose increased levels decrease NLRP3 assembly and inflammatory signaling in cells. We find that methylglyoxal inactivates NLRP3 via a non-enzymatic, covalent-crosslinking-based mechanism, promoting inter- and intraprotein MICA (methyl imidazole crosslink between cysteine and arginine) posttranslational linkages within NLRP3. This work establishes NLRP3 as capable of sensing a host of electrophilic chemicals, both exogenous small molecules and endogenous reactive metabolites, and suggests a mechanism by which glycolytic flux can moderate the activation status of a central inflammatory signaling pathway. [Display omitted] • PGK1 inhibition by CBR-470 compounds inhibits the assembly of the NLRP3 inflammasome • Accumulation of the glycolytic byproduct methylglyoxal inhibits the inflammasome • Methylglyoxal inhibits by modifying NLRP3 via covalent crosslinking MICA modifications Stanton et al. demonstrate that pharmacological inhibition of the glycolytic enzyme PGK1 hinders assembly of the NLRP3 inflammasome. Methylglyoxal, a reactive metabolite that accumulates in response to inhibition of upstream glycolysis, covalently modifies NLRP3 by crosslinking MICA modifications, preventing functional inflammasome assembly. [ABSTRACT FROM AUTHOR]

Anti-cancer drug delivery based on nanocages is important step in drug development process due to reducing side effects and drug-releasing near the tumor cell. We have studied the interaction of the bendamustine anti-cancer drug with the Al/B-N/P nanocages with utilization density functional theory (DFT) approach both in gas and water phases at the B3LYP/6-31G (d,p) level of theory. Results show that the nanocages quantum parameters were somewhat varied by the adsorption of the bendamustine drug. The bendamustine drug operates as an electrons donor and can adsorb in the site of the electron’s acceptor of nanocages. The changes in Gibbs energy correspond to a chemisorption in both phases. The results indicated that the bond between studied nanocages and bendamustine is covalent. However, all studied nanocages may be favorable candidates for detecting the bendamustine drug. Yet, pristine B12P12 and B12N12 nanocages appeared to be more suitable for drug delivery than Al12P12 and Al12N12 based on their recovery times.

Metal-organic porous materials (MOPMs), represented by the famous metal–organic frameworks (MOFs), have attracted extensive attention in recent years. While MOFs are unstable in nature, they are constructed by coordination bond with low bond energies (

Anti-cancer drug delivery based on nanocages is important step in drug development process due to reducing side effects and drug-releasing near the tumor cell. We have studied the interaction of the bendamustine anti-cancer drug with the Al/B-N/P nanocages with utilization density functional theory (DFT) approach both in gas and water phases at the B3LYP/6-31G (d,p) level of theory. Results show that the nanocages quantum parameters were somewhat varied by the adsorption of the bendamustine drug. The bendamustine drug operates as an electrons donor and can adsorb in the site of the electron's acceptor of nanocages. The changes in Gibbs energy correspond to a chemisorption in both phases. The results indicated that the bond between studied nanocages and bendamustine is covalent. However, all studied nanocages may be favorable candidates for detecting the bendamustine drug. Yet, pristine B12P12 and B12N12 nanocages appeared to be more suitable for drug delivery than Al12P12 and Al12N12 based on their recovery times. [ABSTRACT FROM AUTHOR]

The immunoproteasome (iCP) has gained significant interest in recent years as it has been discovered to be significantly expressed under inflammatory conditions, as well as playing significant roles in several diseases, such as autoimmune disorders, viral infection, and cancer. Selective inhibitors have been generated as a method to overcome the off-target effects of current proteasome inhibitor therapeutics. However, selective probes that allow for monitoring this protein complex remain limited, hindering our understanding of the iCP. Current probes are non-selective, not commercially available, or require difficult synthesis. Here, we describe the modular synthesis and application of an iCP-selective probe. The modular nature of the synthetic strategy can enable the incorporation of different fluorophores and covalent warheads, demonstrating the versatility of this probe., (© 2024 Wiley-VCH GmbH.)

Microtubule-stabilizing agents (MSAs) are a class of compounds used in the treatment of triple-negative breast cancer (TNBC), a subtype of breast cancer where chemotherapy remains the standard-of-care for patients. Taxanes like paclitaxel and docetaxel have demonstrated efficacy against TNBC in the clinic, however new classes of MSAs need to be identified due to the rise of taxane resistance in patients. (−)-Zampanolide is a covalent microtubule stabilizer that can circumvent taxane resistance in vitro but has not been evaluated for in vivo antitumor efficacy. Here, we determine that (−)-zampanolide has similar potency and efficacy to paclitaxel in TNBC cell lines, but is significantly more persistent due to its covalent binding. We also provide the first reported in vivo antitumor evaluation of (−)-zampanolide where we determine that it has potent and persistent antitumor efficacy when delivered intratumorally. Future work on zampanolide to further evaluate its pharmacophore and determine ways to improve its systemic therapeutic window would make this compound a potential candidate for clinical development through its ability to circumvent taxane-resistance mechanisms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Redox active and thiol reactive compounds can lead to false positive screening hits. • Optimization of four different high-throughput assays. • Guidelines for detection of redox activity and thiol reactivity. • New promiscuous compounds among bioactive compounds and chemical probes identified. Compounds that exhibit assay interference or undesirable mechanisms of bioactivity are routinely encountered in assays at various stages of drug discovery. We observed that assays for the investigation of thiol-reactive and redox-active compounds have not been collected in a comprehensive review. Here, we review these assays and subject them to experimental optimization to improve their reliability. We demonstrate the usefulness of our assay cascade by assaying a library of bioactive compounds, chemical probes, and a set of approved drugs. These high-throughput assays should complement the array of wet-lab and in silico assays during the initial stages of hit discovery campaigns to pursue only hit compounds with tractable mechanisms of action. [ABSTRACT FROM AUTHOR]

Purpose of Review: Tissue regenerative solutions for musculoskeletal disorders have become increasingly important with a growing aged population. Current growth factor treatments often require high dosages with the potential for off-target effects. Growth factor immobilization strategies offer approaches towards alleviating these concerns. This review summarizes current growth factor immobilization techniques (encapsulation, affinity interactions, and covalent binding) and the effects of immobilization on growth factor loading, release, and bioactivity. Recent Findings: The breadth of immobilization techniques based on encapsulation, affinity, and covalent binding offer multiple methods to improve the therapeutic efficacy of growth factors by controlling bioactivity and release. Growth factor immobilization strategies have evolved to more complex systems with the capacity to load and release multiple growth factors with spatiotemporal control. Summary: The advancements in immobilization strategies allow for development of new, complex musculoskeletal tissue treatment strategies with improved spatiotemporal control of loading, release, and bioactivity. [ABSTRACT FROM AUTHOR]

Emissive covalent organic frameworks (COFs) are a promising class of crystalline materials that have demonstrated applications for sensing and light-emitting diodes. However, white light emission from a single COF has not been achieved yet as it requires multicomponent organic chromophores that simultaneously emit blue, green, and red light. In this work, we report the successful synthesis of a single COF with efficient white light emission by utilizing tunable emission properties of 2,1,3-benzothiadazole after incorporating different functional groups on its core structure, which results in the formation of three ligands, i.e., 4',4-(benzothiadiazole-4,7-diyl)-dibenzaldehyde (BTD), 4,4'-(benzoselenadiazole-4,7-diyl)-dibenzaldehyde (BSD), and 4,4'-(naphtho[2,3- c ][1,2,3] selenadiazole-4,9-diyl)-dibenzaldehyde (NSD), that emit in the blue, green, and red regions of the visible light spectrum. We show that white light emission can only occur when BTD, BSD, and NSD are assembled in a single COF structure due to the facilitated energy transfer process from BTD to BSD/NSD. This work demonstrates a unique approach to developing new white light-emitting materials based on the COF structure.

The modulation of protein-protein interactions with small molecules is one of the most rapidly developing areas in drug discovery. In this review, we discuss advances over the past decade (2014-2023) focusing on molecular glues (MGs)-monovalent small molecules that induce proximity, either by stabilizing native interactions or by inducing neomorphic interactions. We include both serendipitous and rational discoveries and describe the different approaches that were used to identify them. We classify the compounds in three main categories: degradative MGs, non-degradative MGs or PPI stabilizers, and MGs that induce self-association. Diverse, illustrative examples with structural data are described in detail, emphasizing the elements of molecular recognition and cooperative binding at the interface that are fundamental for a MG mechanism of action., Competing Interests: Declaration of interest M.R.A. is a co-founder and consultant of Ambagon Therapeutics., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

[Display omitted] • We have provided clear evidences for the covalent nature of H-bonding interactions in the 2D ice. The uniqueness of all H-bonds in 2D ice lies in the fact that their energies are populated at specific levels, which is fundamentally different from conventional H-bonds in liquid water and water ice. All H-bonds are composed of several different covalent bonding and antibonding states. • The covalent H-bonding interactions are evidenced by the hydrogen intensities in the three-body H-bonding interactions. The covalent interactions of the 1b 2 orbitals are evidenced in the asymmetrically H-bonded cyclic motif, while the symmetrically H-bonded cyclic motif finds the covalent evidences from the 3a 1 orbitals. In particular, the covalent bonding states consisting of pure 1b 2 orbitals strengthen the asymmetrically H-bonded cyclic motif, while the covalent bonding states consisting of pure 3a 1 orbitals strengthen the symmetrically H-bonded cyclic motif. • We have provided clear evidences for the electrostatic nature of H-bonding interactions in the 2D ice. As the vertical waters in asymmetrically H-bonded cyclic motif act as the proton donors when forming interlayer H-bonds, the polarization of OH dipoles along the vertical direction is enhanced. As the vertical water act as the proton acceptors when forming intralayer H-bonds, the oxygen atoms in the horizontal direction exhibit depleted charge density. • The vertical waters in the symmetrically H-bonded cyclic motif always acts as the proton donors, and the OH dipole polarization is enhanced in both the formation of interlayer and intralayer H-bonds, while the internal polarization of the flat-lying water is weakened, which leads to the electrostatic interactions of all H-bonds in both H-bonded cyclic motif exhibiting alternating charge gain and loss states along the proton transfer direction. This is a typical evidence for the electrostatic cooperation of all H-bonding interactions in 2D ice. • The inner water molecule has more charge gain and loss with the metal, indicating that the inner H-bond has more electrostatic interactions than the outer H-bond. These findings significantly advance our understanding on the H-bonding nature in the 2D ices, and they may also have rich implications to fundamental processes in interfacial waters on metal electrodes. Using density functional theory calculations, we provided clear evidence for the covalent and electrostatic nature of rich H-bonds in the 2D ice. Interestingly, we find that all H-bonds consistently populate several different principal states with both the bonding and antibonding features. However, the symmetric and asymmetric H-bonded cycles respectively show preferential HOMO-1 (3a 1) and HOMO-2 (1b 2) contributions to the H-bonding states. For all H-bonding types, alternating positive and negative regions on the second order serve as the direct evidences for the H-bonding electrostatics. Our investigations advance our understanding of the H-bonding nature of rich H-bonds in the ice. [ABSTRACT FROM AUTHOR]

Microtubule-stabilizing agents (MSAs) are a class of compounds used in the treatment of triple-negative breast cancer (TNBC), a subtype of breast cancer where chemotherapy remains the standard-of-care for patients. Taxanes like paclitaxel and docetaxel have demonstrated efficacy against TNBC in the clinic, however new classes of MSAs need to be identified due to the rise of taxane resistance in patients. (−)-Zampanolide is a covalent microtubule stabilizer that can circumvent taxane resistance in vitro but has not been evaluated for in vivo antitumor efficacy. Here, we determine that (−)-zampanolide has similar potency and efficacy to paclitaxel in TNBC cell lines, but is significantly more persistent due to its covalent binding. We also provide the first reported in vivo antitumor evaluation of (−)-zampanolide where we determine that it has potent and persistent antitumor efficacy when delivered intratumorally. Future work on zampanolide to further evaluate its pharmacophore and determine ways to improve its systemic therapeutic window would make this compound a potential candidate for clinical development through its ability to circumvent taxane-resistance mechanisms.

Targeted covalent inhibitors designed to bind covalently to a specific molecular target have recently been a focus of drug development. Among these inhibitors, thiol compounds bind covalently to endogenous thiols in the body through a process involving disulfide bonds. We investigated the predictability of changes in the exposure to captopril, tiopronin, the active form of dalcetrapib and the active metabolite of prasugrel, R-138727, all of which have a sulfhydryl group, in moderate and severe chronic kidney disease (CKD) patients using a constructed PBPK model. The changes in the exposure to captopril, tiopronin and the active form of dalcetrapib under CKD conditions were well predicted. However, the change in exposure to R-138727, which is a secondary metabolite of prasugrel, was overpredicted. Although these thiol compounds covalently bind to endogenous thiols, our study concluded that changes in exposure to these compounds under CKD conditions can probably be predicted, except for compounds with a complicated mechanism whereby the thiol metabolite is generated. [ABSTRACT FROM AUTHOR]

Diamond is widely acknowledged as the hardest naturally occurring material. Nevertheless, when exposed to friction against ferrous metals, it is prone to graphitization or amorphization, which limits the utilization of its extremely high hardness and wear resistance. These issues have persisted for decades without an effective solution. Here, we report that a covalently bonded heterostructure with mixed-dimensional carbons as a high-performance solid lubricant could effectively reduce diamond surface friction and mechanochemical wear with excellent load capacity and durability. When subjected to dry friction and heavy loads (20-150 N), the heterostructure exhibited a notable improvement over pristine diamond with reduced friction coefficients and relative wear rates by 22-45 and 67-91%, respectively. Especially under a 20 N load, the relative wear rate was an order of magnitude lower than that of pristine diamond. Additionally, experiments and molecular dynamics simulations revealed that the heterostructure integrated the outstanding properties of diamond (three-dimensional (3D)), nanographite (3D), and graphene (two-dimensional (2D)), resulting in improved lubrication and antiwear performance that could not be achieved by the individual carbon materials. The findings in this work will be beneficial to overcome the ferrous metal forbidden zone of diamond and are expected to expand the applications of engineered diamond surfaces and graphite/graphene in tribology, mechanics, and electronic fields.

Covalent hits for drug discovery campaigns are neither fantastic beasts nor mythical creatures, they can be routinely identified through electrophile-first screening campaigns using a suite of different techniques. These include biophysical and biochemical methods, cellular approaches, and DNA-encoded libraries. Employing best practice, however, is critical to success. The purpose of this review is to look at state of the art covalent hit identification, how to identify hits from a covalent library and how to select compounds for medicinal chemistry programmes., Competing Interests: Declaration of competing interest All authors are employees of AstraZeneca., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

For three decades the C4a-position of reduced flavins was the known site for covalency within flavoenzymes. The reactivity of this position of the reduced isoalloxazine ring with the dioxygen ground-state triplet established the C4a as a site capable of one-electron chemistry. Within the last two decades new types of reduced flavin reactivity have been documented. These studies reveal that the N5 position is also a protean site of reactivity, that is capable of nucleophilic attack to form covalent bonds with substrates. In addition, though the precise mechanism of dioxygen reactivity is yet to be definitively demonstrated, it is clear that the N5 position is directly involved in substrate oxygenation in some enzymes. In this review we document the lineage of discoveries that identified five unique modes of N5 reactivity that collectively illustrate the versatility of this position of the reduced isoalloxazine ring.

Recently, DNA-PAINT single-molecule localization microscopy (SMLM) has shown great promise for quantitative imaging; however, labelling strategies thus far have relied on multivalent and affinity-based approaches. Here, the covalent labelling of expressed protein tags (SNAP tag and Halo tag) with single DNA-docking strands and application of SMLM via DNA-PAINT is demonstrated. tagPAINT is then used for T-cell receptor signalling proteins at the immune synapse as a proof of principle.

Advances in genomic analyses enable the identification of new proteins that are associated with disease. To validate these targets, tool molecules are required to demonstrate that a ligand can have a disease‐modifying effect. Currently, as tools are reported for only a fraction of the proteome, platforms for ligand discovery are essential to leverage insights from genomic analyses. Fragment screening offers an efficient approach to explore chemical space. Presented here is a fragment‐screening platform, termed PhABits (PhotoAffinity Bits), which utilizes a library of photoreactive fragments to covalently capture fragment–protein interactions. Hits can be profiled to determine potency and the site of crosslinking, and subsequently developed as reporters in a competitive displacement assay to identify novel hit matter. The PhABit platform is envisioned to be widely applicable to novel protein targets, identifying starting points in the development of therapeutics. [ABSTRACT FROM AUTHOR]

Manipulation and engineering of the surfaces has a key role in improving the materials properties. Anchoring of thin hydrogels on the materials surface is one of the recently developed methods to achieve surfaces with high potential applications. Layer‐by‐layer (LBL) has been used widely as a strong strategy for immobilization of thin hydrogel films on the surface of various organic/inorganic substrates. Electrostatic LBL and covalent LBL are two main strategies used in this regard. In electrostatic LBL, negatively and positively hydrophilic polymers are sequentially assembled to create a multilayer hydrogel which subsequent covalent crosslinking of multilayers improved the stability of the inserted layers. On the other hand, covalent LBL requires hydrophilic polymers bearing reactive telechelic groups. These reactive polymers are prepared by various polymerization techniques or by post‐functionalization of biopolymers. The principles of hydrogel anchoring have described along with representative examples. Besides, the potential applications of the modified surfaces in specific cases have been addressed and overviewed. [ABSTRACT FROM AUTHOR]

Understanding the characteristics of nanomaterials in the context of electrode designs for bio‐electrocatalysis is an emerging research direction. Applications for fuel cells, batteries, and biosensors are directly benefited. The objective of this study is to understand the influence of unfunctionalized multiwalled carbon nanotubes (MWNT) in comparison to carboxylated nanotubes (MWNT−COOH) for pi‐pi stacking with 1‐pyrenebutyric acid (Py) and covalent immobilization of bilirubin oxidase (BOD) enzyme toward the resulting oxygen reduction currents. We designed pyrolytic graphite‐edge electrodes modified with MWNT/Py, MWNT−COOH/Py, or only MWNT−COOH for carbodiimide activation and BOD immobilization. The relative increase in surface −COOH groups as we move from MWNT to MWNT/Py to MWNT−COOH/Py modification is voltammetrically estimated. Although the MWNT−COOH/Py displayed the highest relative amount of surface −COOH groups, the oxygen reduction current was the largest for the BOD‐immobilized MWNT/Py electrode than others. Results indicate that unfunctionalized MWNT is the optimal choice for pi‐pi stacking with pyrene linkers and covalent BOD immobilization as biocathode for energy devices. Favorable hydrophobic MWNT surface to interact more closely with the electron‐receiving T1 Cu site of BOD, as opposed to the relatively polar and more defective MWNT−COOH material due to functionalization, is suggested to be one of the underlying factors for the observed electrocatalytic trend. [ABSTRACT FROM AUTHOR]

Determining the charge on an atom in molecules and materials is a long-standing open issue. Quantitative analysis with clear physical picture of charge transfer, electrostatic and covalent contributions to bond energy is highly desirable to advance the understanding of both charge and ionicity. However, the consensus among computations from quantum mechanics to semiempirical methods and state-of-the-art experimental measurement on fractional charge remains elusive. In this work, we generalize Born–Haber thermochemical cycle to compute fractional charge on an atom by delicately balancing the interplay of all interacting components, including charge transfer, electrostatic–covalent interactions and bond energy in molecules. The fractional charge of an atom in solid materials can be also computed straightforwardly with this scheme. [ABSTRACT FROM AUTHOR]

Based on the synergistic effect of the MOF mixed matrix membrane prepared by rotary evaporation and the polydopamine imprinted layer, a boronate-affinity sol–gel double-imprinted UiO-66/PVDF nanocomposite membrane was constructed. [Display omitted] • Imprinted structures based on borate affinity sol–gel dual imprinting synergy was developed. • The application of acetone and rotary evaporation technology promoted the uniform dispersion of MOF particles. • The dopamine-imprinted layer exhibited good adsorption to SA molecules. • The developed membrane achieves high performance flux and permeation selectivity. Compared to traditional separation methods, membrane-based separation can reduce environmental impact while reducing energy consumption. However, traditional adsorbents have issues with low selectivity and adsorption capacity because they enclose the majority of their functional sites in their thick structures. In this research, molecularly imprinted nanocomposite membranes were inventively integrated with boronate-affinity sol–gel imprinting technique (BSIT). It is important to note that in this work, the metal–organic frameworks (MOFs) mixed-matrix membrane (MMMs) served as the initial platform for the polydopamine (PDA)-based imprinting layer. The key to the fabrication of the MOFs MMMs was the employment of the rotary evaporation technique. The prepared boronate-affinity sol–gel molecularly imprinted membranes (BS-MIMs) played an important role in the high selectivity of the specific compound shikimic acid (SA) through covalent (boronate-affinity) and non-covalent (–OH and –NH 2) effect. This new approach provides a more precise combination of simultaneously increasing selectivity (greater than 5.0) and adsorption capacity (up to 107.87 mg g−1). The efficiency of BSIT makes it extremely competitive for the development of selective separation membranes. [ABSTRACT FROM AUTHOR]

[Display omitted] • A potent covalent TTK inhibitor was designed, synthesized and evaluated. • Compound 16 had IC 50 = 0.016 μM on TTK. • Compound 16 showed enhanced kinase selectivity in a panel of kinases. • Mass spectrometry showed 16 binds covalently to the C604 residue of TTK. • Compound 16 significantly inhibited diverse human cancer cells. Threonine tyrosine kinase (TTK) is a critical component of the spindle assembly checkpoint and plays a pivotal role in mitosis. TTK has been identified as a potential therapeutic target for human cancers. Here, we describe our design, synthesis and evaluation of a class of covalent TTK inhibitors, exemplified by 16 (SYL1073). Compound 16 potently inhibits TTK kinase with an IC 50 of 0.016 μM and displays improved selectivity in a panel of kinases. Mass spectrometry analysis reveals that 16 covalently binds to the C604 cysteine residue in the hinge region of the TTK kinase domain. Furthermore, 16 achieves strong potency in inhibiting the growth of various human cancer cell lines, outperforming its relative reversible inhibitor, and eliciting robust downstream effects. Taken together, compound 16 provides a valuable lead compound for further optimization toward the development of drug for treatment of human cancers. [ABSTRACT FROM AUTHOR]

G protein-coupled receptor kinase 5 (GRK5) is an important drug development target for heart failure, cardiac hypertrophy, and cancer. We have designed and developed a new class of highly selective, potent, and non-covalent GRK5 inhibitors. One of the inhibitors displayed GRK5 IC 50 value of 10 nM and exhibited >100,000-fold selectivity over GRK2. The X-ray structure of a ketoamide-derived inhibitor-bound GRK5 showed the formation of a hemithioketal intermediate with active site Cys474 in the GRK5 active site and provided new insights into the ligand-binding site interactions responsible for high selectivity. The current studies serve as an important guide to therapeutic GRK5 inhibitor drug development. [Display omitted] • Design and synthesis of potent and selective GRK5 inhibitors are reported. • Inhibitors form a reversible covalent bond with Cys474 in the active site. • Syntheses of GRK5 inhibitors were achieved in an efficient manner. • Two X-ray crystal structures of inhibitor bound GRK5 were determined. • The X-ray structure shows the formation of a covalent bond with catalytic Cys474. [ABSTRACT FROM AUTHOR]

[Display omitted] In this study, we explored a concise and mild synthetic route to produce novel C-14 arylcarbamate derivatives of andrographolide, a known anti-inflammatory and anticancer natural product. Upon assessing their anti-cancer efficacy against pancreatic ductal adenocarcinoma (PDAC) cells, some derivatives showed stronger cytotoxicity against PANC-1 cells than andrographolide. In addition, we demonstrated one derivative, compound 3m , effectively reduced the expression of oncogenic p53 mutant proteins (p53R273H and p53R248W), proliferation, and migration in PDAC lines, PANC-1 and MIA PaCa-2. Accordingly, the novel derivative holds promise as an anti-cancer agent against pancreatic cancer. In summary, our study broadens the derivative library of andrographolide and develops an arylcarbamate derivative of andrographolide with promising anticancer activity against PDAC. [ABSTRACT FROM AUTHOR]