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The opioid crisis has highlighted the urgent need to develop non‐opioid alternatives for managing pain, with an effective, safe, and non‐addictive pharmacotherapeutic profile. Using an extensive structure–activity relationship approach, here we have identified a new series of highly selective neurotensin receptor type 2 (NTS2) macrocyclic compounds that exert potent, opioid‐independent analgesia in various experimental pain models. To our knowledge, the constrained macrocycle in which the Ile12 residue of NT(7–12) was substituted by cyclopentylalanine, Pro7 and Pro10 were replaced by allyl‐glycine followed by side‐chain to side‐chain cyclization is the most selective analog targeting NTS2 identified to date (Ki 2.9 nM), showing 30,000‐fold selectivity over NTS1. Of particular importance, this macrocyclic analog is also able to potentiate the analgesic effects of morphine in a dose‐ and time‐dependent manner. Exerting complementary analgesic actions via distinct mechanisms of nociceptive transmission, NTS2‐selective macrocycles can therefore be exploited as opioid‐free analgesics or as opioid‐sparing therapeutics, offering superior pain relief with reduced adverse effects to pain patients. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: TAG‐assisted peptide synthesis technology enables optimal conservation of Fmoc amino acid raw materials and chemical solvents while eliminating the need for intricate chromatographic purification processes. This work presents a 4,4'‐diphenylphosphonoxy diphenylcarbinol tag‐mediated liquid‐phase synthesis approach for preparing side‐to‐tail cyclopeptides macolacin which has strong activity against gram‐negative bacteria, and its 15 analogues containing four N‐methylation modified cyclopeptides, as well as an investigation of their structure‐activity relationship (SAR). The synthesis of macolacin analogues primarily focuses on the modifications of the N‐methylation group of Ile‐7 and the tail fatty acyl chain of macolacin. The incorporation of N‐methylation for Ile‐7, along with the dihalogenated or monohalogenated benzoic acids for tail modification, exhibited remarkable antibacterial efficacy and minimal hepatocellular toxicity in vitro. The present study identified an N‐methylation‐modified antimicrobial cyclopeptide Ma14 that exhibits rapid bactericidal efficacy against A. baumanii, etc., while showing reduced hepatocellular toxicity. Molecular docking simulations were conducted to investigate the binding of cyclopeptides to the outer membrane protein BamA of A. baumannii. The findings demonstrated the stable binding interactions of the cyclopeptides with the BamA protein and then presented a novel approach to explain the bacteriostatic mechanism of macolacin‐based cyclopeptide antibiotics. [ABSTRACT FROM AUTHOR]

Peptidylarginine deiminase IV (PADI4, PAD4) deregulation promotes the development of autoimmunity, cancer, atherosclerosis and age-related tissue fibrosis. PADI4 additionally mediates immune responses and cellular reprogramming, although the full extent of its physiological roles is unexplored. Despite detailed molecular knowledge of PADI4 activation in vitro, we lack understanding of its regulation within cells, largely due to a lack of appropriate systems and tools. Here, we develop and apply a set of potent and selective PADI4 modulators. Using the mRNA-display-based RaPID system, we screen >1012 cyclic peptides for high-affinity, conformation-selective binders. We report PADI4_3, a cell-active inhibitor specific for the active conformation of PADI4; PADI4_7, an inert binder, which we functionalise for the isolation and study of cellular PADI4; and PADI4_11, a cell-active PADI4 activator. Structural studies with PADI4_11 reveal an allosteric binding mode that may reflect the mechanism that promotes cellular PADI4 activation. This work contributes to our understanding of PADI4 regulation and provides a toolkit for the study and modulation of PADI4 across (patho)physiological contexts. Walport & coworkers report cell-active, potent and selective cyclic peptide modulators for the enzyme peptidylarginine deiminase PADI4/PAD4, including an inhibitor, an activator and an affinity molecule, revealing insights into PADI4 regulation. [ABSTRACT FROM AUTHOR]

AbstractPeptide-based medications hold immense potential in addressing a wide range of human disorders and discomforts. However, their widespread utilization encounters two major challenges: preservation and production efficiency. Cyclotides, a class of ribosomally synthesized and post-translationally modified peptides (RiPPs), exhibit unique characteristics, such as a cyclic backbone and cystine knot, enhancing their stability and contributing to a wide range of pharmacological properties exhibited by these compounds. Cyclotides are efficient in the biomedical (e.g., antitumor, antidiabetic, antimicrobial, antiviral) and agrochemical fields by exhibiting activity against pests and plant diseases. Furthermore, their structural attributes make them suitable as molecular scaffolds for grafting and drug delivery. Notably, the mutated variant of kalata B1 cyclotide ([T20K] kalata B1) has recently entered phase 1 of human clinical trials for multiple sclerosis, building upon the success observed in animal trials. To enable large-scale production of cyclotides, it is crucial to further explore their remarkable structural and bioactive properties. This necessitates extensive research focused on enhancing the efficiency of the processes required for their production. This study provides a comprehensive review of the biological synthesis methods of cyclotides, with particular emphasis on various expression systems, namely bacteria, plants, yeast, and cell-free systems. By investigating these expression systems, it becomes possible to design production systems that are adaptable, economically viable, and efficient for generating active and pure cyclotides at an industrial scale. The advantages of biological synthesis over chemical synthesis are thoroughly explored, highlighting the potential of these expression systems in meeting the demands of large-scale cyclotide production. [ABSTRACT FROM AUTHOR]

Activating tumor necrosis factor receptor 1 (TNFR1) with tumor necrosis factor alpha (TNFα) is one of the key pathological mechanisms resulting in the exacerbation of rheumatoid arthritis (RA) immune response. Despite various types of drugs being available for the treatment of RA, a series of shortcomings still limits their application. Therefore, developing novel peptide drugs that target TNFα-TNFR1 interaction is expected to expand therapeutic drug options. In this study, the detailed interaction mechanism between TNFα and TNFR1 was elucidated, based on which, a series of linear peptides were initially designed. To overcome its large conformational flexibility, two different head-to-tail cyclization strategies were adopted by adding a proline-glycine (GP) or cysteine-cysteine (CC) to form an amide or disulfide bond between the N-C terminal. The results indicate that two cyclic peptides, R1_CC4 and α_CC8, exhibit the strongest binding free energies. α_CC8 was selected for further optimization using virtual mutations through in vitro activity and toxicity experiments due to its optimal biological activity. The L16R mutant was screened, and its binding affinity to TNFR1 was validated using ELISA assays. This study designed a novel cyclic peptide structure with potential anti-inflammatory properties, possibly bringing an additional choice for the treatment of RA in the future. [ABSTRACT FROM AUTHOR]

The 57th Bürgenstock Conference on Organic Chemistry, held in Switzerland, featured over a hundred scientists from around the world engaging in vibrant scientific discussions. The conference covered a wide range of topics, including non-enzymatic RNA replication, carbon dioxide conversion, organic molecular cages, protein catalyst engineering, and (photo) redox catalysis. Presentations highlighted innovative research in various fields, such as peptide chemistry, metal catalysis, flow processing, and late-stage functionalization, providing valuable insights for the scientific community. [Extracted from the article]

Despite the great advances in discovering cyclic peptides against protein targets, their reduced aqueous solubility, cell permeability, and activity of the cyclic peptide restrict its utilization in advanced biological research and therapeutic applications. Here we report on a novel approach of structural alternation of the exocyclic and linker parts that led to a new derivative with significantly improved cell activity allowing us to dissect its mode of action in detail. We have identified an effective cyclic peptide (CP7) that induces approximately a 9‐fold increase in DNA damage accumulation and a remarkable increase in apoptotic cancer cell death compared to the reported molecule. Notably, treating cells with CP7 leads to a dramatic decrease in the efficiency of non‐homologous end joining (NHEJ) repair of DNA double‐strand breaks (DSBs), which is accompanied by an increase in homologous recombination (HR) repair. Interestingly, treating BRCA1‐deficient cells with CP7 restores HR integrity, which is accompanied by increased resistance to CP7. Additionally, CP7 treatment increases the sensitivity of cancer cells to ionizing radiation. Collectively, our findings demonstrate that CP7 is a selective inhibitor of NHEJ, offering a potential strategy to enhance the effectiveness of radiation therapy. [ABSTRACT FROM AUTHOR]

Scrophulariae Radix (SR), the dried root of Scrophularia ningpoensis Hemsl (S. ningpoensis), has been extensively used as traditional Chinese medicine for thousands of years. However, since the mid-20th century, the traditional processing technology of S. ningpoensis has been interrupted. Therefore, ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry technology, together with a Global Natural Product Social Molecular Networking (GNPS) method, was applied to comprehensively analyze the characteristic changes and mutual transformation of chemical constituents in the differently processed roots of S. ningpoensis, as well as to scientifically elucidate the processing mechanism of differently processed SR. As a result, a total of 149 components were identified. Notably, with the help of the GNPS data platform and MS2 fragment ions, the possible structures of four new compounds (47, 48, 50, and 73) were deduced in differently processed SR samples, in which 47, 48, and 50 are iridoid glycosides, and 73 is a phenylpropanoid glycoside. Five cyclopeptides (78, 86, 97, 99, and 104) derived from leucine (isoleucine) were identified in SR for the first time. The heatmaps analysis results indicated that leucine or isoleucine may be converted to cyclopeptides under the prolonged high-temperature conditions. Moreover, it is found that short-time steaming can effectively prevent the degradation of glycosides by inactivating enzymes. This study provides a new and efficient technical strategy for systematically identifying the chemical components, rapidly discovering the components, and preliminarily clarifying the processing mechanism of S. ningpoensis, as well as also providing a scientific basis for the improvement of the quality standards and field processing of S. ningpoensis. [ABSTRACT FROM AUTHOR]

We report the development of a novel synthetic approach for the highly strained atrop‐Tyr C‐6‐to‐Trp N‐1′ linkage, which can be executed on a decagram scale using a modular strategy involving palladium‐catalyzed C−H arylation followed by Larock macrocyclization. The first total synthesis of lapparbin (1) was achieved by applying this synthetic strategy. Furthermore, the modular synthesis utilizing C−H arylation and Larock macrocyclization, discovered in the total synthesis of lapparbin (1), was demonstrated to be applicable to various arbitrary biaryl linkages, including non‐natural types. [ABSTRACT FROM AUTHOR]

Scorpion toxins are relatively short cyclic peptides (<150 amino acids) that can disrupt the opening/closing mechanisms in cell ion channels. These peptides are widely studied for several reasons including their use in drug discovery. Although improvements in RNAseq have greatly expedited the discovery of new scorpion toxins, their annotation remains challenging, mainly due to their small size. Here, we present a new pipeline to annotate toxins from scorpion transcriptomes using a neural network approach. This pipeline implements basic neural networks to sort amino acid sequences to find those that are likely toxins and thereafter predict the type of toxin represented by the sequence. We anticipate that this pipeline will accelerate the classification of scorpion toxins in forthcoming scorpion genome sequencing projects and potentially serve a useful role in identifying targets for drug development. [ABSTRACT FROM AUTHOR]

As peptide-based therapies gain recognition for their potential anti-cancer activity, cyclic peptides like Sansalvamide A, a marine-derived cyclic depsipeptide, have emerged as a potential anti-cancer agent due to their potent activity against various cancer types in preclinical studies. This review offers a comprehensive overview of Sansalvamide A, including its sources, structure–activity relationship, and semi-synthetic derivatives. The review also aims to outline the mechanisms through which Sansalvamide A and its analogs exert their anti-proliferative effects and to discuss the need for enhancements in pharmacokinetic profiles for better clinical utility. An extensive literature search was conducted, focusing on studies that detailed the anti-cancer activity of Sansalvamide A, its pharmacokinetics, and mechanistic pathways. Data from both in vitro and in vivo studies were collated and analyzed. Sansalvamide A and its analogs demonstrated significant anti-cancer activity across various cancer models, mediated through Hsp 90 inhibition, Topoisomerase inhibition, and G0/G1 cell cycle arrest. However, their pharmacokinetic properties were identified as a significant limitation, requiring improvement for effective clinical translation. Despite its notable anti-cancer effects, the utility of Sansalvamide A is currently limited by its pharmacokinetic characteristics. Therefore, while Sansalvamide A exhibits promise as an anti-cancer agent, there is a compelling need for further clinical and toxicological studies and optimization of its pharmacokinetic profile to fully exploit its therapeutic potential alongside modern cancer therapies. [ABSTRACT FROM AUTHOR]

Cyclotides are plant cyclic peptides with exceptional stability and diverse bioactivity, making them promising candidates for biomedical applications. Therefore, the study of cyclotides has attracted increasing attention in recent years. However, the existing cyclotide detection methods face limitations in sensitivity, accuracy, and reliability. To address these challenges, we developed an integrated strategy using a combination of strong cation exchange chromatography techniques for removing interfering small molecules, Orbitrap Exploris 480 mass spectrometry (OEMS); this is a detection and database searching-based method for cyclotide verification, which greatly improved the sensitivity, accuracy, and reliability of cyclotide identification. This strategy was subsequently employed for cyclotide mapping in Viola with a minute amount of starting tissue, resulting the identification of 65 known and 18 potentially novel cyclotides, which is the largest dataset of cyclotides for Viola philippica. This strategy provided valuable insights into the cyclotide diversity and distribution in V. philippica, with potential applications in drug discovery and other biomedical fields. [ABSTRACT FROM AUTHOR]

Crystalline materials exhibiting non‐centrosymmetry and possessing substantial surface dipole moments play a critical role in piezoelectricity. Designing biocompatible self‐assembled materials with these attributes is particularly challenging when compared to inorganic materials and ceramics. In this study, we elucidate the crystal conformations of novel cyclic peptides that exhibit self‐assembly into tubular structures characterized by unidirectional hydrogen bonding and piezoelectric properties. Unlike cyclic peptides derived from alternating L‐ and D‐amino acids, those derived from new δ‐amino acids demonstrate the formation of self‐assembled tubes with unidirectional hydrogen bonds. Further, the tightly packed tubular assemblies and higher macrodipole moments result in superior piezoelectric coefficients compared to peptides with lower macrodipole moments. Our findings underscore the potential for designing cyclic peptides with unidirectional hydrogen bonds, thereby paving the way for their application in design of biocompatible piezo‐ and ferroelectric materials. [ABSTRACT FROM AUTHOR]

mRNA display is a powerful technology to screen libraries of >1012 cyclic peptides against a protein target, enabling the rapid discovery of high affinity ligands. These cyclic peptides are particularly well suited to challenging protein targets that have been difficult to drug with small molecules. However, target choice can still be limited as screens are typically performed against purified proteins which often demands the use of isolated domains and precludes the use of aggregation‐prone targets. Herein, we report a method to perform mRNA display selections in mammalian cell lysates without the need for prior target purification, vastly expanding the potential target scope of mRNA display. We have applied the methodology to identify low to sub‐nanomolar peptide binders for two targets: a NanoLuc subunit (LgBiT) and full‐length bromodomain‐containing protein 3 (BRD3). Our cyclic peptides for BRD3 were found to bind to the extraterminal (ET) domain of BRD3 and the closely related BRD proteins, BRD2 and BRD4. While many chemical probes exist for the bromodomains of BRD proteins, the ET domain is relatively underexplored, making these peptides valuable additions to the BRD toolbox. [ABSTRACT FROM AUTHOR]

In recent years, there has been an increasing focus on microbial ecology and its possible impact on agricultural production, owing to its eco-friendly nature and sustainable use. The current study employs metabolomics technologies and bioinformatics approaches to identify changes in the exometabolome of Streptomyces albidoflavus B24. This research aims to shed light on the mechanisms and metabolites responsible for the antifungal and growth promotion strategies, with potential applications in sustainable agriculture. Metabolomic analysis was conducted using Q Exactive UPLC-MS/MS. Our findings indicate that a total of 3,840 metabolites were identified, with 137 metabolites exhibiting significant differences divided into 61 up and 75 downregulated metabolites based on VIP >1, |FC| >1, and p < 0.01. The interaction of S. albidoflavus B24 monoculture with the co-culture demonstrated a stronger correlation coefficient. The Principal Component Analysis (PCA) demonstrates that PCA1 accounted for 23.36%, while PCA2 accounted for 20.28% distinction. OPLS-DA score plots indicate significant separation among different groups representing (t1) 24% as the predicted component (to1) depicts 14% as the orthogonal component. According to the findings of this comprehensive study, crude extracts from S. albidoflavus demonstrated varying abilities to impede phytopathogen growth and enhance root and shoot length in tested plants. Through untargeted metabolomics, we discovered numerous potential molecules with antagonistic activity against fungal phytopathogens among the top 10 significant metabolites with the highest absolute log2FC values. These include Tetrangulol, 4-Hydroxybenzaldehyde, and Cyclohexane. Additionally, we identified plant growth-regulating metabolites such as N-Succinyl-L-glutamate, Nicotinic acid, L-Aspartate, and Indole-3-acetamide. The KEGG pathway analysis has highlighted these compounds as potential sources of antimicrobial properties The inhibitory effect of S. albidoflavus crude extracts on pathogen growth is primarily attributed to the presence of specific gene clusters responsible for producing cyclic peptides such as ansamycins, porphyrin, alkaloid derivatives, and neomycin. Overall, it is apparent that crude extracts from S. albidoflavus exhibited varying abilities to inhibit the growth of three phytopathogens and enhancement in both root and shoot length of tested plants. This research enhances our understanding of how secondary metabolites contribute to growth promotion and biocontrol, supporting ecosystem sustainability and resilience while boosting productivity in sustainable agriculture. [ABSTRACT FROM AUTHOR]

We designed and synthesized an N-ortho-nitrobenzylated benzanilide-based amino acid having a cis-amide structure that facilitates cyclization of peptides containing it. Photo-induced removal of the nitrobenzyl group from this residue in the resulting cyclized peptides dramatically alters their conformation and passive membrane permeability via complete cis-amide to trans-amide conversion. [ABSTRACT FROM AUTHOR]

Cyclisation of peptides by forming thioether (lanthionine), disulfide (cystine) or methylene thioacetal bridges between side chains is established as an important tool to stabilise a given structure, enhance metabolic stability and optimise both potency and selectivity. However, a systematic comparative study of the effects of differing bridging modalities on peptide conformation has not previously been carried out. In this paper, we have used the NMR deconvolution algorithm, NAMFIS, to determine the conformational ensembles, in aqueous solution, of three cyclic analogues of angiotensin(1–7), incorporating either disulfide, or non‐reducible thioether or methylene thioacetal bridges. We demonstrate that the major solution conformations are conserved between the different bridged peptides, but the distribution of conformations differs appreciably. This suggests that subtle differences in ring size and bridging structure can be exploited to fine‐tune the conformational properties of cyclic peptides, which may modulate their bioactivities. [ABSTRACT FROM AUTHOR]

The systemic toxicity of cyclic peptides produced by cyanobacteria (CCPs) is not yet completely understood. Apart from the most known damages to the liver and kidneys, symptoms of their neurotoxicity have also been reported. Hepatotoxic CCPs, like microcystins, as well as non-hepatotoxic anabaenopeptins and planktopeptins, all exhibit cytotoxic and cytostatic effects on mammalian cells. However, responses of different cell types to CCPs depend on their specific modes of interaction with cell membranes. This study demonstrates that non-hepatotoxic planktopeptin BL1125 and anabaenopeptins B and F, at concentrations up to 10 µM, affect normal and tumor human astrocytes (NHA and U87-GM) in vitro by their almost immediate insertion into the lipid monolayer. Like microcystin-LR (up to 1 µM), they inhibit Ser/Thr phosphatases and reorganize cytoskeletal elements, with modest effects on their gene expression. Based on the observed effects on intermediate filaments and intermediate filament linkage elements, their direct or indirect influence on tubulin cytoskeletons via post-translational modifications, we conclude that the basic mechanism of CCP toxicities is the induction of inter- and intracellular communication failure. The assessed inhibitory activity on Ser/Thr phosphatases is also crucial since the signal transduction cascades are modulated by phosphorylation/dephosphorylation processes. [ABSTRACT FROM AUTHOR]

Sirtuin 2 (SIRT2), an NAD+-dependent deacetylase, is crucial for regulating vital physiological processes, including aging, DNA repair, and cell cycle progression. Its abnormal activity is linked to diseases such as Parkinson's disease, cancer, and metabolic disorders, making it a potential target for therapeutic intervention. While small molecule inhibitors have been studied, peptide-based inhibitors offer a promising alternative due to their selectivity and bioavailability. This study explores the effects of converting the naturally occurring cyclic inhibitor peptide of SIRT2 (S2iL5) into a non-cyclic form by replacing a residue with FAK (LYS + CF3CO−). The new peptide sequence, Tyr-His-Thr-Tyr-His-Val-FAK (LYS)-Arg-Arg-Thr-Asn-Tyr-Tyr-Cys, was modeled to confirm its stable conformation. Docking studies and MM/GBSA calculations showed that the non-cyclic peptide had a better binding free energy (−50.66 kcal/mol) compared to the cyclic S2iL5 (−49.44 kcal/mol). Further mutations generated 160,000 unique peptides, screened using a machine learning-based QSAR model. Three promising peptides (Peptide 1: YGGNNVKRRTNYYC, Peptide 2: YMGEWVKRRTNYYC, and Peptide 3: YGGNGVKRRTNYYC) were selected and further modeled. Molecular dynamics (MD) analyses demonstrated that Peptide 1 and Peptide 2 had significant potential as SIRT2 inhibitors, showing moderate stability and some structural flexibility. Their best binding free energies were −59.07 kcal/mol and −46.01 kcal/mol, respectively. The study aimed to enhance peptide flexibility and binding affinity, suggesting that optimized peptide-based inhibitors can interact effectively with SIRT2. However, further experimental validation is necessary to confirm these computational predictions and evaluate the therapeutic potential of the identified peptides. [ABSTRACT FROM AUTHOR]

Cyclic peptides are versatile therapeutic agents that boast high binding affinity, minimal toxicity, and the potential to engage challenging protein targets. However, the pharmaceutical utility of cyclic peptides is limited by their low membrane permeability—an essential indicator of oral bioavailability and intracellular targeting. Current machine learning-based models of cyclic peptide permeability show variable performance owing to the limitations of experimental data. Furthermore, these methods use features derived from the whole molecule that have traditionally been used to predict small molecules and ignore the unique structural properties of cyclic peptides. This study presents CycPeptMP: an accurate and efficient method to predict cyclic peptide membrane permeability. We designed features for cyclic peptides at the atom-, monomer-, and peptide-levels and seamlessly integrated these into a fusion model using deep learning technology. Additionally, we applied various data augmentation techniques to enhance model training efficiency using the latest data. The fusion model exhibited excellent prediction performance for the logarithm of permeability, with a mean absolute error of |$0.355$| and correlation coefficient of |$0.883$|⁠. Ablation studies demonstrated that all feature levels contributed and were relatively essential to predicting membrane permeability, confirming the effectiveness of augmentation to improve prediction accuracy. A comparison with a molecular dynamics-based method showed that CycPeptMP accurately predicted peptide permeability, which is otherwise difficult to predict using simulations. [ABSTRACT FROM AUTHOR]

Targeting the class A Beta lactamases Omega loop is an ideal way to combat drug resistance because of its significant role in the catalytic activity and deacylation process inhibition. Therefore, the molecular docking approach with computerized peptide-based in silico screening has been applied for the identification of inhibitors of TEM-type bLs. Among the subjected 105 peptides, Chrombacin (-47.8 KJ/mol), Gassericin A (-35.7 KJ/mol), Duramycin (-34.1 KJ/mol), Brevinin-1DYa (-34.0 KJ/mol), Amoebapore A (-31.2 KJ/mol), Mundticin ATO6 (-29.0 KJ/mol), Lactocyclicin Q (-26.3 KJ/mol), Cinnamycin (-25.9 KJ/mol showed highest binding energy. Among the peptides that showed the highest docking score Elafin, Cinnamycin, Duramycin interacted with Lys 73 of the a domain of catalytic residues of TEM-1 Beta lactamases, whereas Taromycin A, Gassericin A interacted with Lys 234 of the b domain, depicting a strong inhibition and also exhibited desirable physicochemical properties. Hence further in vitro examination of these cyclic peptides against the resistant strains is warranted to help design further novel inhibitors based on their scaffolds and also for the development of an effective drug combination regime. [ABSTRACT FROM AUTHOR]

Two new cyclic peptides, named as cyclogeobomptides A (1) and B (2) were isolated from the roots of Stachys geobombycis C. Y. Wu. Compounds 1 and 2 are both made up of eight amino acids. The structures of them were established on the basis of the spectral data, including mass spectrometry, 2D NMR, and X-ray crystallography. Cyclogeobomptides A and B were proved to have obvious inhibitory activities against α-glucosidase with the IC50 values of 26.00 and 19.16 μM, respectively. [ABSTRACT FROM AUTHOR]

Emerging and reemerging fungal infections are very common in nosocomial and non-nosocomial settings in people having poor immunogenic profiles either due to hematopoietic stem cell transplants or are using immunomodulators to treat chronic inflammatory disease or autoimmune disorders, undergoing cancer therapy or suffering from an immune weakening disease like HIV. The refractory behavior of opportunistic fungi has necessitated the discovery of unconventional antifungals. The emergence of black fungus infection during COVID-19 also triggered the antifungal discovery program. Natural products are one of the alternative sources of antifungals. Endophytic fungi reside and co-evolve within their host plants and, therefore, offer a unique bioresource of novel chemical scaffolds with an array of bioactivities. Hence, immense possibilities exist that these unique chemical scaffolds expressed by the endophytic fungi may play a crucial role in overcoming the burgeoning antimicrobial resistance. These chemical scaffolds so expressed by these endophytic fungi comprise an array of chemical classes beginning from cyclic peptides, sesquiterpenoids, phenols, anthraquinones, coumarins, etc. In this study, endophytic fungi reported in the last six years (2018–2023) have been explored to document the antifungal entities they produce. Approximately 244 antifungal metabolites have been documented in this period by different groups of fungi existing as endophytes. Various aspects of these antifungal metabolites, such as antifungal potential and their chemical structures, have been presented. Yet another unique aspect of this review is the exploration of volatile antifungal compounds produced by these endophytic fungi. Further strategies like epigenetic modifications by chemical as well as biological methods and OSMAC to induce the silent gene clusters have also been presented to generate unprecedented bioactive compounds from these endophytic fungi. [ABSTRACT FROM AUTHOR]

Targeting the class A Beta lactamases Omega loop is an ideal way to combat drug resistance because of its significant role in the catalytic activity and deacylation process inhibition. Therefore, the molecular docking approach with computerized peptide-based in silico screening has been applied for the identification of inhibitors of TEM-type βLs. Among the subjected 105 peptides, Chrombacin (-47.8 KJ/mol), Gassericin A (-35.7 KJ/mol), Duramycin (-34.1 KJ/mol), Brevinin-1DYa (-34.0 KJ/mol), Amoebapore A (-31.2 KJ/mol), Mundticin ATO6 (-29.0 KJ/mol), Lactocyclicin Q (-26.3 KJ/mol), Cinnamycin (-25.9 KJ/mol showed highest binding energy. Among the peptides that showed the highest docking score Elafin, Cinnamycin, Duramycin interacted with Lys 73 of the α domain of catalytic residues of TEM-1 Beta lactamases, whereas Taromycin A, Gassericin A interacted with Lys 234 of the β domain, depicting a strong inhibition and also exhibited desirable physicochemical properties. Hence further in vitro examination of these cyclic peptides against the resistant strains is warranted to help design further novel inhibitors based on their scaffolds and also for the development of an effective drug combination regime.

Cyclic peptides have emerged as versatile scaffolds in drug discovery due to their stability and specificity. Here, we present the cPEPmatch webserver (accessible at https://t38webservices.nat.tum.de/cpepmatch/), an easy-to-use interface for the rational design of cyclic peptides targeting protein-protein interactions combined with a semi-quantitative evaluation of binding stability. This platform also offers access to a comprehensive database of cyclic peptide crystal structures. We demonstrate the webserver's utility through a series of case studies involving medically relevant protein systems, highlighting its potential to significantly advance drug discovery efforts.

Cyclic peptides present a robust platform for drug design, offering high specificity and stability due to their conformationally constrained structures. In this study, we introduce an updated version of the Cyclic Peptide Matching program (cPEPmatch) tailored for the identification of cyclic peptides capable of mimicking protein-glycosaminoglycan (GAG) binding sites. We focused on engineering cyclic peptides to replicate the GAG-binding affinity of antithrombin III (ATIII), a protein that plays a crucial role in modulating anticoagulation through interaction with the GAG heparin. By integrating computational and experimental methods, we successfully identified a cyclic peptide binder with promising potential for future optimization. MD simulations and MM-GBSA calculations were used to assess binding efficacy, supplemented by umbrella sampling to approximate free energy landscapes. The binding specificity was further validated through NMR and ITC experiments. Our findings demonstrate that the computationally designed cyclic peptides effectively target GAGs, suggesting their potential as novel therapeutic agents. This study advances our understanding of peptide-GAG interactions and lays the groundwork for future development of cyclic peptide-based therapeutics.

The study of cyclic peptides (CPs) and self-assembling cyclic peptide nanotubes (SCPNs) is pivotal in advancing applications in diverse fields such as biomedicine, nanoelectronics, and catalysis. Recognizing the limitations in the experimental study of these molecules, this article introduces CYCLOPEp Builder, a comprehensive web-based application designed to facilitate the design, simulation, and visualization of CPs and SCPNs. The tool is engineered to generate molecular topologies, essential for conducting Molecular Dynamics simulations that span All-Atom to Coarse-Grain resolutions. CYCLOPEp Builder's user-friendly interface simplifies the complex process of molecular modeling, providing researchers with the ability to readily construct CPs and SCPNs. The platform is versatile, equipped with various force fields, and capable of producing structures ranging from individual CPs to complex SCPNs with different sequences, offering parallel and antiparallel orientations among them. By enhancing the capacity for detailed visualization of molecular assemblies, CYCLOPEp Builder improves the understanding of CP and SCPN molecular interactions. This tool is a step forward in democratizing access to sophisticated simulations, offering an invaluable resource to the scientific community engaged in the exploration of supramolecular structures. CYCLOPEp is accessible at http://cyclopep.com/

Comprehensive Summary: The first total synthesis of neopetromin, featuring the highly strained Tyr C‐6‐to‐Trp N‐1' linkage, is hereby reported. This modular synthetic strategy, employing C—H arylation and Larock macrocyclization, offers a novel approach to the synthesis of various RiPPs natural product families. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The first total synthesis of neopetromin, featuring the highly strained Tyr C‐6‐to‐Trp N‐1' linkage, is hereby reported. This modular synthetic strategy, employing C—H arylation and Larock macrocyclization, offers a novel approach to the synthesis of various RiPPs natural product families. [ABSTRACT FROM AUTHOR]

Artificial light‐harvesting systems (LHSs) with a multi‐step sequential energy transfer mechanism significantly enhance light energy utilization. Nonetheless, most of these systems exhibit an overall energy transfer efficiency below 80%. Moreover, due to challenges in molecularly aligning multiple donor/acceptor chromophores, systems featuring ≥3‐step sequential energy transfer are rarely reported. Here, a series of artificial LHSs is introduced featuring up to 4‐step energy transfer mechanism, constructed using a cyclic peptide‐based supramolecular scaffold. These LHSs showed remarkably high energy transfer efficiencies (≥90%) and satisfactory fluorescence quantum yields (ranging from 17.6% to 58.4%). Furthermore, the structural robustness of the supramolecular scaffold enables a comprehensive study of these systems, elucidating the associated energy transfer pathways, and identifying additional energy transfer processes beyond the targeted sequential energy transfer. Overall, this comprehensive investigation not only enhances the understanding of these LHSs, but also underscores the versatility of cyclic peptide‐based supramolecular scaffolds in advancing energy harvesting technologies. [ABSTRACT FROM AUTHOR]

Background Excessive pulmonary inflammation and damage are characteristic features of severe influenza virus infections. LAT8881 is a synthetic 16–amino acid cyclic peptide form of a naturally occurring C-terminal fragment of human growth hormone with therapeutic efficacy against influenza. Shorter linear peptides are typically easier to manufacture and formulate for delivery than larger cyclic peptides. A 6–amino acid linear peptide fragment of LAT8881, LAT9997, was investigated as a potential influenza therapy. Methods LAT9997 was evaluated for its potential to limit disease in a preclinical mouse model of severe influenza infection. Results Intranasal treatment of mice with either LAT8881 or LAT9997 from day 1 following influenza infection significantly improved survival outcomes. Initiating LAT9997 treatment at the onset of severe disease also significantly improved disease severity. Greater disease resistance in LAT9997-treated mice correlated with reduced lung immunopathology, damage markers, vascular leak, and epithelial cell death. Treatment reduced viral loads, cytokines, and neutrophil infiltration in the airways yet maintained protective alveolar macrophages in a dose-dependent manner. Sequential trimming of N- and C-terminal amino acids from LAT9997 revealed a structure-activity relationship. Conclusions These findings provide preclinical evidence that therapeutic LAT9997 treatment limits viral burden and characteristic features of severe influenza, including hyperinflammation and lung damage. Summary Excessive pulmonary inflammation and damage are characteristic features of severe influenza virus infections. LAT9997 is a linear peptide fragment derived from human growth hormone. This study provides preclinical evidence that therapeutic LAT9997 treatment limits viral burden, hyperinflammation, and lung damage. [ABSTRACT FROM AUTHOR]

Ethynylbenziodoxol(on)es (EB(X)xs) reagents have emerged as useful reagents for peptide/protein modification due to their versatile reactivity and high selectivity. Herein, we report the successful introduction of ethynylbenziodoxoles (EBxs) on different amino acid building blocks (Lys/Orn/Dap), and show their compatibility with both solid phase peptide synthesis (SPPS) and solution phase peptide synthesis (SPS). The selective incorporation of the EBx core into peptide sequences enable efficient macrocyclizations under mild conditions for the synthesis of topologically unique cyclic and bicyclic peptides. [ABSTRACT FROM AUTHOR]

The development of novel antivirals is crucial not only for managing current COVID‐19 infections but for addressing potential future zoonotic outbreaks. SARS‐CoV‐2 main protease (Mpro) is vital for viral replication and viability and therefore serves as an attractive target for antiviral intervention. Herein, we report the optimization of a cyclic peptide inhibitor that emerged from an mRNA display selection against the SARS‐CoV‐2 Mpro to enhance its cell permeability and in vitro antiviral activity. By identifying mutation‐tolerant amino acid residues within the peptide sequence, we describe the development of a second‐generation Mpro inhibitor bearing five cyclohexylalanine residues. This cyclic peptide analogue exhibited significantly improved cell permeability and antiviral activity compared to the parent peptide. This approach highlights the importance of optimizing cyclic peptide hits for activity against intracellular targets such as the SARS‐CoV‐2 Mpro. [ABSTRACT FROM AUTHOR]

Motivation There has been a burgeoning interest in cyclic peptide therapeutics due to their various outstanding advantages and strong potential for drug formation. However, it is undoubtedly costly and inefficient to use traditional wet lab methods to clarify their biological activities. Using artificial intelligence instead is a more energy-efficient and faster approach. MuCoCP aims to build a complete pre-trained model for extracting potential features of cyclic peptides, which can be fine-tuned to accurately predict cyclic peptide bioactivity on various downstream tasks. To maximize its effectiveness, we use a novel data augmentation method based on a priori chemical knowledge and multiple unsupervised training objective functions to greatly improve the information-grabbing ability of the model. Results To assay the efficacy of the model, we conducted validation on the membrane-permeability of cyclic peptides which achieved an accuracy of 0.87 and R-squared of 0.503 on CycPeptMPDB using semi-supervised training and obtained an accuracy of 0.84 and R-squared of 0.384 using a model with frozen parameters on an external dataset. This result has achieved state-of-the-art, which substantiates the stability and generalization capability of MuCoCP. It means that MuCoCP can fully explore the high-dimensional information of cyclic peptides and make accurate predictions on downstream bioactivity tasks, which will serve as a guide for the future de novo design of cyclic peptide drugs and promote the development of cyclic peptide drugs. Availability and implementation All code used in our proposed method can be found at https://github.com/lennonyu11234/MuCoCP. [ABSTRACT FROM AUTHOR]

The legume albumin-1 gene family, arising after nodulation, encodes linear a- and b-chain peptides for nutrient storage and defense. Intriguingly, in one prominent legume, Clitoria ternatea, the b-chains are replaced by domains producing ultra-stable cyclic peptides called cyclotides. The mechanism of this gene hijacking is until now unknown. Cyclotides require recruitment of ligase-type asparaginyl endopeptidases (AEPs) for maturation (cyclization), necessitating co-evolution of two gene families. Here we compare a chromosome-level C. ternatea genome with grain legumes to reveal an 8 to 40-fold expansion of the albumin-1 gene family, enabling the additional loci to undergo diversification. Iterative rounds of albumin-1 duplication and diversification create four albumin-1 enriched genomic islands encoding cyclotides, where they are physically grouped by similar pI and net charge values. We identify an ancestral hydrolytic AEP that exhibits neofunctionalization and multiple duplication events to yield two ligase-type AEPs. We propose cyclotides arise by convergence in C. ternatea where their presence enhances defense from biotic attack, thus increasing fitness compared to lineages with linear b-chains and ultimately driving the replacement of b-chains with cyclotides. Genomic innovation in plant defense is explored by the authors who uncover the genome-wide hijacking of the albumin-1 gene family by biocidal cyclic peptides called cyclotides, and recruitment of asparaginyl endopeptidases for peptide cyclization. [ABSTRACT FROM AUTHOR]

Molecular dynamics (MD) simulation is a powerful tool for characterizing ligand–protein conformational dynamics and offers significant advantages over docking and other rigid structure-based computational methods. However, setting up, running, and analyzing MD simulations continues to be a multi-step process making it cumbersome to assess a library of ligands in a protein binding pocket using MD. We present an automated workflow that streamlines setting up, running, and analyzing Desmond MD simulations for protein–ligand complexes using machine learning (ML) models. The workflow takes a library of pre-docked ligands and a prepared protein structure as input, sets up and runs MD with each protein–ligand complex, and generates simulation fingerprints for each ligand. Simulation fingerprints (SimFP) capture protein–ligand compatibility, including stability of different ligand-pocket interactions and other useful metrics that enable easy rank-ordering of the ligand library for pocket optimization. SimFPs from a ligand library are used to build & deploy ML models that predict binding assay outcomes and automatically infer important interactions. Unlike relative free-energy methods that are constrained to assess ligands with high chemical similarity, ML models based on SimFPs can accommodate diverse ligand sets. We present two case studies on how SimFP helps delineate structure–activity relationship (SAR) trends and explain potency differences across matched-molecular pairs of (1) cyclic peptides targeting PD-L1 and (2) small molecule inhibitors targeting CDK9. [ABSTRACT FROM AUTHOR]

While peptide macrocycles with rigidified conformations have proven to be useful in the design of chemical probes of protein targets, conformational flexibility and rapid interconversion can be equally vital for biological activity and favorable physicochemical properties. This study introduces the concept of "structural pin", which describes a hydrogen bond that is largely responsible for stabilizing the entire macrocycle backbone conformation. Structural analysis of macrocycles using nuclear magnetic resonance (NMR), molecular modelling and X‐ray diffraction indicates that disruption of the structural pin can drastically influence the conformation of the entire ring, resulting in novel states with increased flexibility. This finding provides a new tool to interrogate dynamic behaviour of macrocycles. Identification of structural pins offers a useful conceptual framework to understand positions that can either be modified to give flexible structures or retained to maintain the rigidity of the scaffold. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) are promising tools for combating microbial resistance. However, their therapeutic potential is hindered by two intrinsic drawbacks—low target affinity and poor in vivo stability. Macrocyclization, a process that improves the pharmacological properties and bioactivity of peptides, can address these limitations. As a result, macrocyclic peptides represent attractive drug candidates. Moreover, many drugs are macrocycles that originated from natural product scaffolds, suggesting that nature offers solutions to the challenges faced by AMPs. In this review, we explore natural cyclic peptides from the DBAASP database. DBAASP is a comprehensive repository of data on antimicrobial/cytotoxic activities and structures of peptides. We analyze the data on small (≤25 AA) ribosomal and non-ribosomal cyclic peptides from DBAASP according to their amino acid composition, bonds used for cyclization, targets they act on, and mechanisms of action. This analysis will enhance our understanding of the small cyclic peptides that nature has provided to defend living organisms. [ABSTRACT FROM AUTHOR]

In the realm of therapeutic peptides, tremendous progress has been achieved in the last two decades. The building block of peptides that is, 'Amino Acid' has been modified by various chemical modifications such as side‐chain alteration in linear peptides, cyclization, back‐bone modification, pro‐drug moiety, conjugation with heterocycles, and natural products to make peptides a foremost candidate as a therapeutic drug. Since the advent of insulin in 1922, peptides have immensely affected the development of the pharmaceutical industry giving rise to the peptide‐based drug industry. In recent years, peptides having antimicrobial, antiviral, anti‐tumor, anti‐inflammatory, anti‐aging, and antioxidant properties have developed. Also, it has now entered as a potent candidate in the field of oncology and also become a valuable tool as a radiolabeled peptide for the detection of various diseases. Generally, peptides were extracted from natural sources in the olden days, but presently work is directed towards finding alternate and sustainable ways for developing synthetic peptides. The present review covers the discussion about the historic evaluation of peptides, available effective synthetic processes, current advancements, use of bioinformatic tools, computational strategies, and the methodology to overcome the barrier for making peptides the potent candidate for the future world. [ABSTRACT FROM AUTHOR]

Influenza viruses are the leading cause of upper respiratory tract infections, leading to several global pandemics and threats to public health. Due to the continuous mutation of influenza A viruses, there is a constant need for the development of novel antiviral therapeutics. Recently, natural antimicrobial peptides have provided an opportunity for the discovery of anti-influenza molecules. Here, we designed several peptides based on pheasant cathelicidin and tested their antiviral activities and mechanisms against the H1N1 virus. Of note, the designed peptides Pc-4 and Pc-5 were found to inhibit replication of the H1N1 virus with an IC50 = 8.14 ± 3.94 µM and 2.47 ± 1.95 µM, respectively. In addition, the cyclic peptide Pc-5 was found to induce type I interferons and the expression of interferon-induced genes. An animal study showed that the cyclic peptide Pc-5 effectively inhibited H1N1 virus infection in a mouse model. Taken together, our work reveals a strategy for designing cyclic peptides and provides novel molecules with therapeutic potential against influenza A virus infection. [ABSTRACT FROM AUTHOR]

Macrocycles offer an attractive format for drug development due to their good binding properties and potential to cross cell membranes. To efficiently identify macrocyclic ligands for new targets, methods for the synthesis and screening of large combinatorial libraries of small cyclic peptides were developed, many of them using thiol groups for efficient peptide macrocyclization. However, a weakness of these libraries is that invariant thiol‐containing building blocks such as cysteine are used, resulting in a region that does not contribute to library diversity but increases molecule size. Herein, we synthesized a series of structurally diverse thiol‐containing elements and used them for the combinatorial synthesis of a 2,688‐member library of small, structurally diverse peptidic macrocycles with unprecedented skeletal complexity. We then used this library to discover potent thrombin and plasma kallikrein inhibitors, some also demonstrating favorable membrane permeability. X‐ray structure analysis of macrocycle‐target complexes showed that the size and shape of the newly developed thiol elements are key for binding. The strategy and library format presented in this work significantly enhance structural diversity by allowing combinatorial modifications to a previously invariant region of peptide macrocycles, which may be broadly applied in the development of membrane permeable therapeutics. [ABSTRACT FROM AUTHOR]

The cyanobacterium Prochloron didemni, an obligate symbiont of different species of colonial ascidians, occurring in the Pacific and Indian Oceans, produces a variety of cyclic peptides. These patellamide‐type macrocycles lead to relatively stable dicopper(II) complexes that are extremely efficient carbonic anhydrase mimics, the most active model systems known so far. Importantly, it recently was shown that copper(II) is coordinated to patellamide derivatives in Prochloron cells. An interesting question therefore is, whether the biological function of patellamide‐type macrocycles is related to the catalytic activity in CO2 hydration or its reverse. Here, we present a computational study to evaluate the energetics of the catalytic cycle in search of a possible answer to these questions and compare the computed energy barriers with the experimental kinetic data. It emerges that release of the bridging carbonate is a critical step and that the catalysis product inhibits catalysis at pH values above approx. 7. Therefore, carbonate transport rather than CO2 hydrolysis is proposed as the biological function of copper(II)‐patellamide complexes in the Prochloron‐Ascidian symbiosis. [ABSTRACT FROM AUTHOR]

The SPRY domain-containing SOCS box proteins SPSB1, SPSB2, and SPSB4 utilize their SPRY/B30.2 domain to interact with a short region in the N-terminus of inducible nitric oxide synthase (iNOS), and recruit an E3 ubiquitin ligase complex to polyubiquitinate iNOS, resulting in the proteasomal degradation of iNOS. Inhibitors that can disrupt the endogenous SPSB-iNOS interactions could be used to augment cellular NO production, and may have antimicrobial and anticancer activities. We previously reported the rational design of a cyclic peptide inhibitor, cR8, cyclo(RGDINNNV), which bound to SPSB2 with moderate affinity. We, therefore, sought to develop SPSB inhibitors with higher affinity. Here, we show that cyclic peptides cR7, cyclo(RGDINNN), and cR9, cyclo(RGDINNNVE), have ~6.5-fold and ~2-fold, respectively, higher SPSB2-bindng affinities than cR8. We determined high-resolution crystal structures of the SPSB2-cR7 and SPSB2-cR9 complexes, which enabled a good understanding of the structure–activity relationships for these cyclic peptide inhibitors. Moreover, we show that these cyclic peptides displace full-length iNOS from SPSB2, SPSB1, and SPSB4, and that their inhibitory potencies correlate well with their SPSB2-binding affinities. The strongest inhibition was observed for cR7 against all three iNOS-binding SPSB proteins. [ABSTRACT FROM AUTHOR]

Background: Fibroblast activation protein (FAP) has emerged as a promising target for diagnosis and therapeutic intervention due to high expression and accumulation in the stromal compartments of a variety of malignant tumors. FAP-2286 utilizes cyclic peptides with FAP-binding characteristics to enhance the retention of the imaging agent within tumors, in contrast to the small-molecule FAP inhibitors (FAPI) like FAPI-04/46. The aim of this study was to quantify the tumor uptake of [68Ga] Gallium-FAP-2286 within primary solid tumors, adjacent excised tissues, and metastatic lesions. Methods: In this prospective study, 21 patients (average age 51.9) with various diagnoses of remaining and metastatic cancers participated. Among them, six had metastatic sarcoma, and 14 had adenocarcinoma, including eight breast, two rectum, two lung, two pancreas, and one thyroid cases. The patients underwent a [68Ga]Ga-FAP-2286 PET/CT scan. An hour post-administration of [68Ga]Ga-FAP-2286, a visual assessment of whole body scans and semi-quantification of the PET/CT results were carried out. The standardized uptake values (SUV)max of [68Ga]Ga-FAP-2286 in tumor lesions and the tumor-to-background ratio (TBR) were then calculated. Results: The vital signs of the patients, such as heart rate, blood pressure, and temperature, were observed before, during, and after the diagnostic procedure during the 4-h follow-up. All individuals underwent the [68Ga]Ga-FAP-2286 PET/CT scans without any signs of drug-associated pharmacological effects. The PET/CT scans displayed substantial absorption of [68Ga]Ga-FAP-2286 in tumor lesions in all patients (100% (21/21)). Irrespective of the tumors' origins (epithelial or mesothelium) and whether they exhibited local recurrence, distant recurrence, or metastatic lesions, the PET/CT scans revealed the uptake of [68Ga]Ga-FAP-2286 in these lesions. Conclusion: Overall, these data suggest that [68Ga]Ga-FAP-2286 is a promising FAP derivative for efficient metastatic cancer diagnosis and being considered as a potential compound for therapeutic application in patients with advanced metastatic cancers. [ABSTRACT FROM AUTHOR]

The cannabinoid type 2 receptor (CB2R), a G protein–coupled receptor, is an important regulator of immune cell function and a promising target to treat chronic inflammation and fibrosis. While CB2R is typically targeted by small molecules, including endo-, phyto-, and synthetic cannabinoids, peptides–owing to their size–may offer a different interaction space to facilitate differential interactions with the receptor. Here, we explore plant-derived cyclic cystine-knot peptides as ligands of the CB2R. Cyclotides are known for their exceptional biochemical stability. Recently, they gained attention as G protein–coupled receptor modulators and as templates for designing peptide ligands with improved pharmacokinetic properties over linear peptides. Cyclotide-based ligands for CB2R were profiled based on a peptide-enriched extract library comprising nine plants. Employing pharmacology-guided fractionation and peptidomics, we identified the cyclotide vodo-C1 from sweet violet (Viola odorata) as a full agonist of CB2R with an affinity (Ki) of 1 μM and a potency (EC50) of 8 μM. Leveraging deep learning networks, we verified the structural topology of vodo-C1 and modeled its molecular volume in comparison to the CB2R ligand binding pocket. In a fragment-based approach, we designed and characterized vodo-C1-based bicyclic peptides (vBCL1-4), aiming to reduce size and improve potency. Opposite to vodo-C1, the vBCL peptides lacked the ability to activate the receptor but acted as negative allosteric modulators or neutral antagonists of CB2R. This study introduces a macrocyclic peptide phytocannabinoid, which served as a template for the development of synthetic CB2R peptide modulators. These findings offer opportunities for future peptide-based probe and drug development at cannabinoid receptors. [ABSTRACT FROM AUTHOR]

Chemical pesticides remain the predominant method for pest management in numerous countries. Given the current landscape of agriculture, the development of biopesticides has become increasingly crucial. The strategy empowers farmers to efficiently manage pests and diseases, while prioritizing minimal adverse effects on the environment and human health, hence fostering sustainable management. In recent years, there has been a growing interest and optimism surrounding the utilization of peptide biopesticides for crop protection. These sustainable and environmentally friendly substances have been recognized as viable alternatives to synthetic pesticides due to their outstanding environmental compatibility and efficacy. Numerous studies have been conducted to synthesize and identify peptides that exhibit activity against significant plant pathogens. One of the peptide classes is cyclotides, which are cyclic cysteine‐rich peptides renowned for their wide range of sequences and functions. In this review, we conducted a comprehensive analysis of cyclotides, focusing on their structural attributes, developmental history, significant biological functions in crop protection, techniques for identification and investigation, and the application of biotechnology to enhance cyclotide synthesis. The objective is to emphasize the considerable potential of cyclotides as the next generation of plant protection agents on the global scale. [ABSTRACT FROM AUTHOR]

Researchers have developed a polymer-based coating for textiles that can keep the wearer cool by deflecting the sun's rays and radiating away body heat. The coating, inspired by crushed limestone plasters used in hot climates, reflects UV and near-IR light. The coated fabric was found to be up to 15°F cooler than untreated fabric. The manufacturing process is sustainable and solvent-free, and the cost of the coating is less than $1 per linear yard. In another study, language models (LLMs) were used to explore sequences of amino acids and proteins. LLMs, originally designed for text, can be applied to proteins by clustering them based on similar functions. Researchers used artificial intelligence (AI) to re-engineer an existing antibiotic called Protegrin-1, which destroys bacterial membranes. The article also highlights the concerning prediction that by 2050, antimicrobial resistance could lead to ten million deaths per year. [Extracted from the article]