SCFSkp2/Cks1 E3 ubiquitin ligase complex

Proteolysis-targeting chimera (PROTAC) has been developed to be a useful technology for targeted protein degradation. PROTACs consist of a ligand for E3 ligase (E3 ligase binder), a linker and a ligand (mostly small-molecule inhibitor) for protein of interest（target binder）. Upon binding to the target protein, the PROTACs can recruit E3 for target protein ubiquitination, which is subjected to proteasome-mediated degradation.

Although there are more than 600 E3 ubiquitin ligases, only several with small molecule ligands have been used for designing PROTACs, including Skp1-Cullin-F box complex containing Hrt1 (SCF), Von Hippel-Lindau tumor suppressor (VHL), Cereblon (CRBN), inhibitor of apoptosis proteins (IAPs), and mouse double minute 2 homolog (MDM2).

MCE carefully prepared a unique collection of 174 ligands for E3 ligase, which have been reported to be used in PROTAC design. MCE E3 ligase ligand library is a useful tool for PROTAC development.

Protein ubiquitination is an enzymatic post-translational modification in which an ubiquitin protein is attached to a substrate protein. Ubiquitination involves three main steps: activation, conjugation, and ligation, performed by ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s), and ubiquitin ligases (E3s), respectively. Ubiquitination affects cellular processes such as apoptosis, cell cycle, DNA damage repair, and membrane transportation, etc. by regulating the degradation of proteins (via the proteasome and lysosome), altering the cellular localization of proteins, affecting proteins activity, and promoting or preventing protein-protein interactions. Deregulation of ubiquitin pathway leads to many diseases such as neurodegeneration, cancer, infection and immunity, etc.

MCE offers a unique collection of 482 small molecule modulators with biological activity used for ubiquitination research. Compounds in this library target the key enzymes in ubiquitin pathway. MCE Ubiquitination Compound Library is a useful tool for the research of ubiquitination regulation and the corresponding diseases.

CRBN, namely cereblon, is the substrate recognition subunit of the E3 ubiquitin ligase complex in the ubiquitin-proteasome system. A CRBN ligand library refers to a collection of numerous fragments that can specifically bind to the CRBN protein.

These ligands are mostly designed based on validated CRBN-binding warheads and modified through AI-driven molecular generation optimization systems. They not only include classic lenalidomide-derived structures but also cover novel non-lenalidomide scaffolds. After drug-likeness filtering, these ligands exhibit structural diversity and favorable druggable properties. They can be further optimized and modified to facilitate the development of novel molecular glue degraders, accelerate the discovery of molecular glues that induce interactions between CRBN and new substrate proteins, and enable the exploration of novel CRBN substrates for identifying previously unknown CRBN-binding proteins.

MCE compiles 125 fragments that can specifically bind to the CRBN protein, with molecular weights ranging from 200 to 500. Compounds developed based on the library ligands target multiple disease targets such as cancer and autoimmune diseases, further advancing the development of Molecular Glues and PROTACs therapeutic agents.

Targeted Protein Degradation (TPD) is a novel and promising approach to drug development. It shows great potential for targeting proteins traditionally considered "undruggable" due to the lack of enzymatic function and absence of binding sites by tagging them for degradation or recruiting natural degradation mechanisms.

Molecular glues are a type of small-molecule degraders that primarily induce novel interactions between E3 ubiquitin ligases and target proteins, forming ternary complexes that lead to protein ubiquitination and subsequent proteasomal degradation. Compared with PROTACs, molecular glues generally have lower molecular weights, higher cell permeability, and better drug-like properties. Additionally, the design of molecular glues is relatively simple, without the requirements for complex linkers and ligand optimization. As a result, molecular glues have gradually emerged as a promising therapeutic approach for various diseases.

Multiple types of molecular glues have been reported previously. Analysis of co-crystal complex structures reveals that CRBN-related molecular glues are more versatile. Therefore, MCE researchers select active molecules related to these targets as probes for artificial intelligence (AI) screening.Subsequently, molecular docking technology was used to verify whether the screened molecules retained the key pharmacophore features. Ultimately, we obtained 317 molecular glue analogs, and these compounds serve as powerful tools for the research of molecular glues.

Targeted protein degradation(TPD) is a novel and promising approach to new drug discovery and development. It shows great potential for treating diseases with “undruggable” pathogenic protein targets and for overcoming drug resistance. Molecular glues and PROTACs are both targeted protein degraders that have attracted the most attention.

Molecular glues are small molecular degraders that mainly induce novel interaction between an E3 ligase and a target protein to form a ternary complex, leading to protein ubiquitination and subsequent proteasome degradation. Compared with PROTACs, molecular glues generally possess more favorable drug-like properties, such as lower MW, higher cell permeability, and better oral absorption. Molecular glues are emerging as a promising new therapeutic strategy.

MCE supplies a unique collection of 105 molecular glues which target various proteins. MCE Molecular Glue Compound Library is a useful tool to conduct scientific research and disease mechanism study.

The cytoskeleton is responsible for contraction, cell motility, movement of organelles and vesicles through the cytoplasm, cytokinesis, intracellular signal transduction, and many other functions that are essential for cellular homeostasis and survival. It accomplishes these tasks through three basic structures: F-actin, microtubules, and intermediate filaments (IFs). The cytoskeleton is a dynamic structure where the three major filaments and tubules are under the influence of proteins that regulate their length, state of polymerization, and level of cross-linking. Since cytoskeleton is involved in virtually all cellular processes, cytoskeletal protein aberrations are the underlying reason for many pathological phenotypes, including several cardiovascular disease syndromes, neurodegeneration, cancer, liver cirrhosis, pulmonary fibrosis, and blistering skin diseases.

MCE designs a unique collection of 2,148 cytoskeleton-related compounds mainly focusing on the key targets in the cytoskeleton signal pathway and can be used in the research of cytoskeleton signal pathway and related diseases.

Pulmonary fibrosis (PF), also known as diffuse interstitial pulmonary fibrosis, is a very common end-stage manifestation of several diseases, including idiopathic pulmonary fibrosis (IPF), pulmonary hypertension, and scleroderma, characterised by excessive matrix deposition and destruction of the lung architecture, finally leading to respiratory insufficiency. PF has become a global disease with significantly increased incidence rate, and the most common form of pulmonary fibrosis is idiopathic pulmonary fibrosis (IPF).

Lung fibrosis is a complex disease, a multitude of signal factors and signaling pathways is disrupted in this complex disease, such as TGF-β, Wnt, VEGF and PI3K–Akt. MCE offers a unique collection of 2,653 compounds with identified and potential anti-pulmonary fibrosis activity. MCE Anti-Pulmonary Fibrosis Compound Library is a useful tool for anti-pulmonary fibrosis drugs screening and other related research.

Metabolomics is the large-scale study of cellular metabolic complement, with proven utility in both basic and applied studies of plants, microorganisms, and mammals. As an important tool for the study of complex biological systems, metabolomics monitors the complex molecular networks that exist in the natural flow of information from genes to mRNA and proteins to organisms. The metabolome is composed of biomolecules that most closely resemble the phenotype of an organism, and changes in its composition can easily lead to the production of diseases. Therefore, metabolomics has received much attention in drug target discovery, drug response and translational research of disease mechanisms. Mass spectrometry-based metabolomics methods can simultaneously detect and quantify thousands of metabolite signatures, thereby characterizing the pathophysiological mechanisms of various biomedical symptoms.

MCE can provide 664 mass spectrometry human endogenous metabolites that can be used for metabolite identification and quantification, functional cell detection and phenotypic screening of mass spectrometry.

POI (Protein of Interest) refers to the target protein, namely the disease-causing protein or key functional protein that undergoes degradation or functional modulation in molecular glue-mediated processes. The Molecular Glue POI Library consists of a series of fragments that can specifically bind to different types of POIs. As key components of molecular glues, these ligands form stable interactions with target proteins, laying the foundation for molecular glues to induce the interaction between POIs and E3 ubiquitin ligases. The covered POIs include various types such as cancer-associated GSPT1, androgen receptors, and abnormally aggregated proteins linked to neurodegenerative diseases.

This fragment library can be applied to the screening and optimization of targeted protein degraders. By screening ligands with high affinity and strong selectivity for specific POIs from the library, core structures can be identified to develop novel molecular glues. For instance, optimization of ligands targeting GSPT1 has yielded molecular glue degraders with enhanced degradation activity. Since many POIs are difficult to drug due to the lack of traditional small-molecule binding pockets, some ligands in the POI Ligand Library can modulate such POIs by inducing protein-protein interactions, thereby further expanding the scope of drug discovery for undruggable targets.

MCE has compiled a POI Fragment Library comprising thousands of POI fragments with molecular weights ranging from 150 to 400. This compound library can be widely applied in Molecular Glue research and development.

Proteolysis-targeting chimera (PROTAC) has been developed to be a useful technology for targeted protein degradation. PROTACs consist of a ligand for E3 ligase (E3 ligase binder), a linker and a ligand (mostly small-molecule inhibitor) for protein of interest（target binder）. Upon binding to the target protein, the PROTACs can recruit E3 for target protein ubiquitination, which is subjected to proteasome-mediated degradation. Therefore, PROTACs execute their functions by degrading the target proteins rather than inhibiting them, which has a great superiority in overcoming resistance caused by target mutation or overexpression. To date, PROTAC technology has been applied to a variety of targets, including AR, ER, BTK, BET, and BCR-ABL to overcome resistance.

MCE carefully prepared a unique collection of 94 ligands for target proteins, which have been reported to be used in PROTAC design. MCE Target Protein Ligand Library is a useful tool for PROTAC development.

PROTACs (Proteolysis-targeting chimeras) is a class of molecules that utilize ubiquitin-proteasome system (UPS) to ubiquitinate and degrade target proteins. The PROTACs molecule consists of two ligands joined by a linker. The one-to-one interaction between PROTACs and target proteins determines the high efficiency of PROTACs, making it a potential molecule for targeted protein degradation (TPD) therapy.

MCE supplies a unique collection of 515 PROTACs that effectively degrade target proteins with more powerful screening capability. MCE PROTAC Library is a useful tool for signal pathway research, protein degradation therapy research, drug discovery and drug repurposing, etc.

Sulfonyl fluoride (-SO₂F) overcomes the bottleneck of target selectivity in traditional covalent warheads through its unique chemical and biological properties, which rely heavily on cysteine (Cys) residues. Featuring high stability and tunable electrophilicity under physiological conditions, it can target a wide range of nucleophilic residues including lysine (Lys), tyrosine (Tyr), serine (Ser), and histidine (His). It offers the advantages of a broader druggable space, lower off-target risks, and long-lasting efficacy, with numerous reported cases in the research of covalent inhibitors, Molecular glue, PROTACs, and chemical biology probe development.

MCE constructs a highly diverse sulfonyl fluoride fragment library based on the reactivity, stability and physiological compatibility of sulfonyl fluoride. The library contains 1000 efficiently synthesized and stable sulfonyl fluoride fragments, which ensure precise reactivity of the warhead and retain sufficient derivatization space for subsequent optimization. Combined with the modular strategy of SuFEx click chemistry, it enables versatile modification of compounds and functionalization of complex molecules, improves the efficiency of structural optimization and rapidly expands druggability, making it suitable for high-throughput probe and custom covalent library construction. It provides an efficient research tool for the development of broad-spectrum covalent inhibitors targeting Lys/Tyr/Ser/His, covalent PROTACs for E3 ligases and chemical biology probe development, meeting the requirements of modern drug research for high throughput, high success rate and high derivatization potential.

This library contains 1,162 sulfonyl fluoride fragments with high structural diversity, favorable drug-like properties and tunable electrophilicity. It is well suited for precise targeting of non-Cys residues and meets the criteria of simple structure and high derivatization potential. It effectively improves

Mitochondrial autophagy refers to the selective encapsulation and degradation of damaged mitochondria by cells through the autophagy mechanism, thereby maintaining mitochondrial and cellular homeostasis. The concept of mitochondrial autophagy has received extensive attention since it was proposed. Current studies have shown that the mechanisms of mitochondrial autophagy can generally be divided into two categories: Ubiquitin-dependent pathways and Ub-independent pathways. In addition, mitochondrial autophagy is a research hotspot related to the pathogenesis of neurodegenerative diseases, cardiovascular diseases, cancer, metabolic diseases and other clinical diseases. Therefore, high-throughput screening based on mitochondrial autophagy can effectively screen out compounds that are closely related to the occurrence of diseases and analyze their mechanisms.

MCE can provide a library of 601 mitophagy compounds, which can be used for drug development and mechanism research in cancer, immunity, infection and other hot research fields.

The blood-brain barrier (BBB) is the complex network of brain microvessels. It protects the brain from the external bloodstream environment and supplies the brain with the required nutrients for normal function. However, blood-brain barrier is also the obstacle to deliver beneficial drugs to treat CNS (central nervous system) diseases or brain tumors, as it has the least permeable capillaries in the entire body due to physical barriers (tight junctions). Therefore, it is crucial to discover drugs which can cross this barrier for the treatment of brain-based diseases, such as Alzheimer’s disease (AD), Parkinson’s disease (PD) and epilepsy.

MCE offers a unique collection of 1,096 compounds with confirmed CNS-Penetrant property. It’s a useful tool for the discovery of drugs used for brain diseases, such as brain tumors, mental disorders, and neurodegenerative diseases.

Alkaloids are a large and complex group of cyclic compounds that contain N. About 2,000 different alkaloids have been isolated. Important alkaloids include morphine, strychnine, atropine, colchicine, ephedrine, quinine, and nicotine. Alkaloids are useful as diet ingredients, supplements, and pharmaceuticals, in medicine and in other applications in human life. They showed anti-inflammatory, anticancer, analgesics, local anesthetic and pain relief, neuropharmacologic, antimicrobial, antifungal, and many other activities. Alkaloids are also important compounds in organic synthesis for searching new semisynthetic and synthetic compounds with possibly better biological activity than parent compounds.

MCE designs a unique collection of 599 alkaloids that all come from natural products. MCE Alkaloids Library is a useful tool for drug discovery that can be used for high throughput screening (HTS) and high content screening (HCS).

Rheumatoid Arthritis (RA) is a autoimmune disease characterized by persistent joint inflammation. The pathology of RA includes immune cell infiltration, synovial lining proliferation, pannus formation, and the destruction of joint cartilage and bone, which is highly disabling. Due to long-term chronic inflammation, RA not only severely affects the quality of life of patients but can also damage multiple organs, leading to lung diseases, cardiovascular diseases, and malignant tumors. The pathogenesis of RA is complex, involving genetic, environmental, and immune factors. With the advancement of high-throughput screening technology, screening for compounds targeting JAK, CCR, MEK, MMP targets may contribute to the development of more effective drugs against Rheumatoid Arthritis (RA).

MCE has collected 1,883 small molecule compounds with definite or potential anti-rheumatoid arthritis activity. This library is of significant value for researching the anti-RA drugs.

Cell proliferation, the increase in cell numbers resulting from cell division, is a complex and tightly regulated process. Cell proliferation is regulated by coordinated entry into the cell cycle, and changes in proliferation are closely linked to disease development. Evolutionary dynamics links tumor growth and progression with cell proliferation, cell death, and mutation rates. In addition, cell proliferation is central to degenerative diseases, the development of which is often accompanied by accelerated multiplication of cancer cells. Therefore, assays of cell proliferation levels are frequently used for laboratory research purposes and increasingly for clinical assessment of tumor aggressiveness and potentially to guide care. It has been shown that multiple key targets are collectively involved in regulating the process of cell proliferation, such as CDK, E2F, pRB, β-Catenin, and others.

MCE collects 3,398 compounds that target and regulate key targets of cell proliferation, which can be used in studies of cell proliferation mechanisms and drug discovery.

MAPK families play an important role in complex cellular programs like proliferation, differentiation, development, transformation, and apoptosis. In mammalian cells, four MAPK families have been clearly characterized: ERK1/2, C-Jun N-terminal kinse/stress-activated protein kinase (JNK/SAPK) , p38 kinase and ERK5. They respond to different signals. Each MAPK-related cascade consists of three enzymes that are activated in series: a MAPK kinase kinase (MAPKKK), a MAPK kinase (MAPKK) and a MAP kinase (MAPK). MAPK signaling pathways has been implicated in the development of many human diseases including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and various types of cancers.

MCE designs a unique collection of 1,063 MAPK signaling pathway inhibitors that act as a useful tool for MAPK-related drug screening and disease research.

Hormones are a class of biologically active substances secreted by endocrine gland cells, which are transported through the circulatory system to various parts of the body, and precisely act on specific target organs or cells, playing a crucial role in regulating the growth, development, metabolism, and reproduction of organisms. The mechanisms of hormone action are diverse and complex. Some hormones (such as corticosteroids, vitamin D, and thyroid hormones) can enter the cell interior and interact with receptors in the nucleus, thereby regulating gene expression and affecting cell function. Other hormones (such as growth hormone and thyrotropin-releasing hormone) bind directly to receptors on the cell surface, exerting their effects by regulating enzyme activity or influencing the state of ion channels. Additionally, hormones play a key role in the study of endocrine and metabolic diseases, and are closely related to the development of diseases such as diabetes and thyroid diseases.

MCE has included 86 human hormone compounds, which is of great significance for the study of human metabolic pathways, and can also be used to build a metabonomics database.

The occurrence of diseases is often associated with multiple targets and pathways, and the factors of disease formation are complex and diverse, so the development of more powerful drugs is needed. According to statistics, 21% of the FDA-approved drugs in 2015-2017 were multi-target compounds. Multi-target compounds refer to a drug targeting multiple disease-related targets or multiple subtypes of a target. Multi-target compounds can be applied to drug screening or targeted ligand design. Because the targets of such compounds are diverse and clear, they have the characteristics of saving time and drug cost during the mechanism research of new drug research and development. In addition, due to the diversity of drug targets, multiple strategies can be applied to pharmacological studies.

MCE supplies a unique collection of 6,758 multi-target compounds that targets two or more different targets or different subtypes of the same target. MCE Multi-Target Compound Library can be used for target protein ligand screening or drug development.

Inflammasomes are classic pattern recognition receptors for natural immune responses. Inflammasomes are polymeric protein complexes that regulate inflammatory responses and pyrolytic cell death, thereby exerting the host's defense against microorganisms. Inflammasomes sensors are associated with adapter proteins, activating inflammatory caspase-1, releasing inflammatory cytokines and inducing cell death, endowing the host with defense against pathogens. NLRP1, NLRP3, NLRC4, AIM2, and pyrin are considered typical inflammasomes because they convert cysteine asparaginase-1 into catalytically active capsaicin-1. In addition to infectious diseases, the importance of inflammasomes is also related to various clinical diseases, such as autoimmune diseases, neurodegeneration and metabolic disorders, and the development of cancer. Therefore, it is necessary to strictly regulate the activation and function of inflammasomes to avoid accidental host tissue damage while inducing pathogens to kill the inflammatory response.

MCE designs a unique collection of 163 inflammasomes related compounds. It is a good tool to be used for research on Inflammation, cancer and other diseases.

Cosmetics are complex mixtures formulated through the rational blending and processing of various natural, synthetic, or extracted raw materials. The ingredients used in cosmetics are diverse in type and functionality. Based on their properties and applications, cosmetic ingredients can generally be classified into two main categories: base materials and auxiliary ingredients. The former constitutes the primary component of cosmetics, accounting for a significant proportion in formulations and serving as the key functional substances. Auxiliary ingredients, on the other hand, play roles in shaping the product, ensuring stability, or imparting color, fragrance, and other specific characteristics.Establishing a systematic ingredient database is of great significance for cosmetic research and development. By analyzing the physicochemical properties (such as oil-water partition coefficients and molecular weight distribution), biological activity mechanisms (such as antioxidant pathways and cellular signaling regulation), and compatibility of ingredients, the database can provide precise guidance for formulation design. This approach helps shorten the development cycle of cosmetic/skincare products and reduces trial-and-error costs.

MCE offers 622 types of cosmetic ingredient compounds, including antioxidants, humectants, emulsifiers, film-forming agents, and more.

Miao medicine is an important part of Chinese medicine, which carries the profound cultural heritage and rich life wisdom of the Hmongb people. Miao people live in a concentrated community in the mountainous area of the southwest border of China, which has a unique natural environment. Complex and diverse geology, lush natural vegetation, rich animal and plant species, a large number of mineral resources which provide a wide range of species sources for miao ethnicity medicine. On the other hand, due to the characteristics of the living environment of the Hmongb people, Miao medicine has demonstrated its unique therapeutic effect in the treatment of some endemic diseases, infectious diseases, insect, snake and beast bites, rheumatism and other diseases. With the development of modern science and technology, the research and application of seedling medicine are also deepening. Through the systematic study of the chemical composition and pharmacological action of the seedling medicine, it can provide a new idea and method for modern medicine.

MCE included 1,639 natural products from traditional miao ethnicity medicine, including animal, plant and mineral sources.

Peptides, composed of amino acids, serve as crucial building blocks for proteins and have gained significant attention in drug development over the past decade. The advancements in production, modification, and analytical technologies have led to a surge in the potential applications of peptides in medicine. Peptides offer a number of advantages over small molecule drugs, including: greater target specificity and efficacy, more predictable metabolic profiles, easier delivery to where they are needed in the body, and fewer side effects. Peptides are increasingly appearing in all branches of medicine as components of innovative drugs, imaging agents, diagnostic agents, and other complex drugs such as peptide-drug conjugates. To date, more than 80 peptide drugs have been approved to treat a variety of diseases, including microbial infections, obesity, anti-diabetes, and cancer, as well as to develop cell targeting platforms and improve cell penetration properties.

MCE designs a unique collection of 826 peptide compounds. HY-L105S is a peptide compound library that can be provided with solution form based on HY-L105, and can be applied to peptides-based drug development.

Tuberculosis (TB), usually caused by bacteria (Mycobacterium tuberculosis), is an infectious disease that mainly affects the lungs. According to the statistics of the World Health Organization (WHO), 10 million people suffer from tuberculosis every year, and 1.5 million people die of tuberculosis every year, which makes tuberculosis the number one killer of infectious diseases.

Tuberculosis can be cured through the standard 6-month course of treatment of four kinds of antibiotics. Common drugs include rifampicin and isoniazid. In some cases, TB bacteria do not respond to standard drugs, that is, patients with drug-resistant tuberculosis. The treatment of drug-resistant tuberculosis takes longer and is more complex. In the face of the resurgence of tuberculosis in the world and the rapid emergence of multi drug resistant tuberculosis, it is very important to develop new anti-tuberculosis drugs or new clinical treatment schemes for existing anti mycobacterium drugs.

MCE supplies a unique collection of 151 compounds with clear anti-tuberculosis activity. MCE Anti-tuberculosis Compound Library is a useful tool for anti-tuberculosis related research and anti-tuberculosis drug development

Aging is a complex biological process characterized by functional decline of tissues and organs, structural degeneration, and reduced adaptability and resistance, all of which contribute to an increase in morbidity and mortality caused by multiple chronic diseases, such as Alzheimer's disease, cancer, and diabetes. Many theories, which fall into two main categories: programmed and error theories, have been proposed to explain the process of aging, but neither of them appears to be fully satisfactory. The programmed theories imply that aging relies on specific gene regulation, and the error theories emphasize the internal and environmental damages accumulated to living organisms. The damage theories proposed the nine hallmarks that were generally considered to contribute to the aging process: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient-sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication.

MCE Anti-Aging Compound Library contains 7,297 compounds, mainly targeting Sirtuin, mTOR, IGF-1R, AMPK, p53, Telomerase, Mitophagy, Mitochondrial Metabolism, COX, Cytochrome P450, Oxidase, etc. This library is a useful tool for anti-aging research.

Tonifying traditional Chinese medicines occupy a central position in the traditional medical system, with their core value lying in the regulation of the body's functional state. Modern pharmacological studies have confirmed that these medicinal materials and their monomeric components possess multiple biological activities, including bidirectional immune regulation, anti-aging and lifespan extension, neuroprotection and cognitive enhancement, as well as hematopoietic and metabolic regulation. According to the traditional Chinese medicine theory of “strengthening the body’s resistance and consolidating the foundation”, tonifying medicines are mainly classified into four major categories: Qi-tonifying, Blood-tonifying, Yin-tonifying, and Yang-tonifying. This compound library strictly follows this classification system for compound collection.

Monomeric compounds derived from traditional Chinese medicines demonstrate excellent drug-like properties. They naturally possess structural diversity and clearly defined pharmacological activities, which help improve screening success rates and make them ideal tools for studying multi-target synergistic effects. This library contains 1,036 compounds, providing a material basis for investigating synergistic interactions among compounds (network pharmacology) and facilitating the development of multi-target therapeutic strategies for complex diseases such as cancer, neurodegenerative disorders, and metabolic syndrome.

The transforming growth factor beta (TGF-β) signaling pathway is involved in many cellular processes in both the adult organism and the developing embryo including cell growth, cell differentiation, apoptosis, cellular homeostasis and other cellular functions. The TGF-β superfamily comprises TGF-βs, bone morphogenetic proteins (BMPs), activins and related proteins. Signaling begins with the binding of a TGF beta superfamily ligand to a TGF beta type II receptor. The type II receptor is a serine/threonine receptor kinase, which catalyzes the phosphorylation of the Type I receptor. The type I receptor then phosphorylates receptor-regulated SMADs (R-SMADs) which can now bind the coSMAD (e.g. SMAD4). R-SMAD/coSMAD complexes accumulate in the nucleus where they act as transcription factors and participate in the regulation of target gene expression. Deregulation of TGF-β signaling contributes to developmental defects and human diseases, including cancers, some bone diseases, chronic kidney disease, etc.

MCE designs a unique collection of 413 TGF-beta/Smad signaling pathway compounds. TGF-beta/Smad Compound Library acts as a useful tool for TGF-beta/Smad-related drug screening and disease research.

Molecular Glue Virtual Library is constructed using generative AI technology, integrating the structural features, activity data of known molecular glues, and interaction information of ternary complexes (target protein-E3-molecular glue). Endowed with structural novelty, drug-likeness, diversity and synthesizability, it is applicable to molecular glue-based AI drug screening and large-scale virtual screening.

MCE builds this library based on high-quality molecular building blocks by virtue of robust computing power, coupled with rigorous reaction rules and optimized compound generation strategies. To ensure library quality, molecules with high synthetic difficulty, poor drug-likeness, PAINS and other undesirable molecules are excluded first. Subsequently, scaffold-based compound analysis is performed to screen drug-like diverse molecules for synthesizability evaluation; those with excessively high synthetic difficulty are removed, ultimately forming a large-scale molecular glue virtual library with structural diversity, synthesizability and drug-likeness.

Compounds in the library can be synthesized in only 1-2 chemical reaction steps. With MCE’s experienced chemical synthesis team, custom synthesis of different scales from milligram to kilogram can be easily achieved to meet diverse customer needs.

Owing to the high conservation of orthosteric sites, conventional orthosteric drugs frequently suffer from poor subtype selectivity, off-target toxicity, and drug resistance, severely restricting their clinical application. In contrast, allosteric sites feature low conservation, high hydrophobicity, weak polarity, confined spatial geometry, and dynamic cryptic properties. These characteristics endow allosteric modulators with distinct advantages including high selectivity, functional tunability, and improved safety, making allosteric therapy a key direction in modern drug discovery.

MCE has curated nearly 1,000 structurally disclosed clinical-stage allosteric modulators. By analyzing allosteric protein–ligand complex structures from the PDB database, we extracted core pharmacophores and privileged scaffolds. Adopting a rational design strategy of “scaffold derivation + allosteric physicochemical filtering”, we performed secondary screening on the derived compounds strictly following the optimal physicochemical principles for allosteric binding based on universal allosteric pocket properties: molecular weight 300–500 Da, HBD ≤ 3, HBA = 3–8, PSA = 70–120 Ų, rotatable bonds ≤ 6, highly rigid scaffolds, cLogP = 1.0–3.8, and no strongly ionizable groups. The selected compounds exhibit high rigidity and shape complementarity, making them well-suited for targeting shallow, dynamic, and hydrophobic-dominated allosteric pockets.

This allosteric modulator library contains 4,315 structurally diverse, lead-like compounds dedicated to allosteric drug development, allosteric site targeting, and allosteric modulator screening. It is suitable for kinases, GPCRs, and other important drug targets. All compounds are analogs of clinical-stage allosteric modulators with a similarity score > 0.6, combining excellent druggability and allosteric binding potential. It provides a highly efficient tool for early-stage allosteric drug discovery.