Protein structure

Protein tyrosine kinases (PTKs) are key signaling molecules and important drug targets. Two classes of PTKs are present in cells: the transmembrane receptor PTKs (RTKs) and the nonreceptor PTKs. The RTK family includes the receptors for insulin and for many growth factors, such as EGFR, FGFR, PDGFR, VEGFR, and NGFR. RTKs are transmembrane glycoproteins that are activated by the binding of their ligands, and they transduce the extracellular signal to the cytoplasm by phosphorylating tyrosine residues on the receptors themselves (autophosphorylation) and on downstream signaling proteins. Their principal functions of PTKs involve the regulation of multicellular aspects of the organism. Cell to cell signals concerning growth, differentiation, adhesion, motility, and death are frequently transmitted through tyrosine kinases. In humans, tyrosine kinases have been demonstrated to play significant roles in the development of many disease states, including diabetes and cancers.

MCE designs a unique collection of 1,695 compounds that act as a useful tool for PTKs-related drug screening and disease research.

Boronic acid and boronic ester represent a relatively novel and promising chemical structure in drug design. Boronic acid exists in an sp²-hybridized state, possessing an empty p-orbital that can act as a Lewis acid to accept lone pairs from heteroatoms (O, N, or S). This Lewis acidity enables it to form reversible covalent bonds with amino acid residues such as lysine, serine, threonine, and histidine. Currently, five FDA-approved drugs containing boronic acid or boronic ester predominantly involve such covalent binding mechanisms in their interactions with target proteins. Furthermore, boronic acid can serve as a bioisostere for carboxylic acids, phosphates, and phenolic groups, utilized to improve pharmacokinetic properties and enhance drug efficacy.

To date, five boron-containing drugs have been approved by the FDA. The unique properties of boronic acids and boronic esters confer significant potential in drug design, with applications spanning cancer therapy (e.g., multiple myeloma), anti-infectives (e.g., fungal infections, tuberculosis), anti-inflammatory treatments (e.g., atopic dermatitis), antibacterial agents (e.g., carbapenem-resistant bacterial infections), and Reactive Oxygen Species (ROS)-responsive prodrugs, among others. The MCE Boronic Acid/Boronic Ester Fragment Library, which contains 1,488 compounds, serves as a valuable tool for the development of boron-containing drugs.

The RNA-targeted bioactive compound library is a high-quality collection of small molecules specifically designed and curated to target RNA structures and functions. It is widely applied in cutting-edge drug discovery and life science research. Unlike traditional strategies that focus on protein targets, RNA-targeted compounds can directly modulate various functional RNA molecules by influencing their splicing, translation, stability, or structural conformation, thereby enabling precise intervention in key biological processes. In the field of drug development, these compounds provide a novel approach to addressing previously “undruggable” targets and have demonstrated significant potential in areas such as oncology, antiviral therapies, and neurodegenerative diseases. For example, by targeting disease-associated RNA structural domains or regulating the aberrant expression of non-coding RNAs, these compounds can effectively inhibit disease progression or restore normal cellular function. In mechanistic studies, RNA-targeted compounds serve as valuable chemical biology tools to elucidate the roles of RNA in gene expression regulation, cellular signaling pathways, and disease development.

The MCE RNA-targeted bioactive compound library contains 858 compounds, sourced from databases such as TargetRX Atlas and R-BIND. The library features excellent structural diversity and biological activity, making it suitable for high-throughput screening (HTS), target validation, phenotypic screening, and lead compound discovery. It represents a valuable resource for RNA-related research and innovative drug development.

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

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 128 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.

Small molecule covalent inhibitors, or irreversible inhibitors, are a type of inhibitors that exert their biological functions by irreversibly binding to target through covalent bonds. Compared with non-covalent inhibitors, covalent inhibitors have obvious advantages in bioactivity, such that covalent warheads can target rare residues of a particular target protein, thus leading to the development of highly selective inhibitors and achieving a more complete and continued target occupancy in living systems. In recent years, the distinct strengths of covalent inhibitors in overcoming drug resistance had been recognized. However, toxicity can be a real challenge related to this class of therapeutics due to their potential for off-target reactivity and has led to these drugs being disfavored as a drug class. The drug design and optimization of covalent inhibitors has become a hot spot in drug discovery.

MCE covalent inhibitor library contains 6,121 small molecules including identified covalent inhibitors and other molecules having common covalent reactive groups as warheads, such as acrylamides, activated terminal acetylenes, sulfonyl fluorides/esters, cloracetamides, alkyl halides, epoxides, aziridines, disulfides, etc.

MCE Covalent inhibitor Library plus, with more powerful screening capability, further complement Covalent inhibitor Library (HY-L036) by adding some fragment compounds with covalent warheads.

Protein Kinases (PTKs) are a class of phosphotransferases that phosphorylate proteins. Protein kinases participate in many signal transduction pathways including those involved with growth, differentiation, and cell division. Protein kinase not only plays an important role in the process of cell activation, but also its abnormal expression is closely related to the pathogenesis of many diseases. So far, the protein kinase family has become one of the most important drug targets. The most common drug targets include ALK, B-Raf, BCR-Abl, EGFR, and VEGFR.

MCE designs a unique collection of 4,585 bioactive compounds targeting protein kinases, which is an important tool for the development of drug targeting protein kinases.

Small molecule covalent inhibitors, or irreversible inhibitors, are a type of inhibitors that exert their biological functions by irreversibly binding to target through covalent bonds. Compared with non-covalent inhibitors, covalent inhibitors have obvious advantages in bioactivity, such that covalent warheads can target rare residues of a particular target protein, thus leading to the development of highly selective inhibitors and achieving a more complete and continued target occupancy in living systems. In recent years, the distinct strengths of covalent inhibitors in overcoming drug resistance had been recognized. However, toxicity can be a real challenge related to this class of therapeutics due to their potential for off-target reactivity and has led to these drugs being disfavored as a drug class. The drug design and optimization of covalent inhibitors has become a hot spot in drug discovery.

MCE covalent inhibitor library contains 1,618 small molecules including identified covalent inhibitors and other bioactive molecules having common covalent reactive groups as warheads, such as acrylamides, activated terminal acetylenes, Sulfonyl fluorides/esters, cloracetamides, alkyl halides, epoxides, aziridines, disulfides, etc.

Metabolism is the set of life-sustaining chemical reactions in organisms that maintain cell homeostasis. Metabolic pathways are enzyme-mediated biochemical reactions that lead to biosynthesis (anabolism) or breakdown (catabolism) of molecules including glucose metabolism, lipid metabolism and amino acid or protein metabolism within a cell or tissue. As catalysts, enzymes are crucial to metabolism as they allow a reaction to proceed more rapidly and tregulate the rate of a metabolic reaction. Due to the importance of metabolic balance in the organism, the abnormal function of metabolic enzymes often leads to the occurrence of a variety of metabolic diseases, such as diabetes, obesity, cardiovascular disease, etc.

MCE designs a unique collection of 4,407 metabolic enzymes related small molecules, which is an important tool for studying the metabolic activities of organisms and developing drugs for metabolic diseases.

Kinases is a class of enzymes that adds chemicals called phosphates to other molecules, such as sugars or proteins. Protein phosphorylation serves as a critical regulatory mechanism for numerous cellular processes including cell division, metabolism, and signal transduction, with approximately 50% of cellular functions in humans being regulated by kinase activity. In drug discovery, kinases represent a major category of therapeutic targets, and kinase inhibitors constitute an important class of pharmaceuticals that block the activity of specific disease-associated enzymes, particularly in cancer and inflammatory disorders. Small molecule kinase inhibitors represent one of the fastest-growing drug categories, having received U.S. Food and Drug Administration (FDA) approval for both oncological and non-oncological indications. As of September 2023, over 70 FDA-approved small molecule kinase inhibitors are commercially available.

The MCE Kinase Inhibitor Library Mini contains 270 kinase inhibitors primarily targeting protein kinases (VEGFR, EGFR, BTK, CDK, Akt, etc.), lipid kinases (PI3K, PI4K, SK, etc.), and carbohydrate kinases. This collection includes 1-3 highly specific representative compounds per target, optimized for screening of kinase-related drug targets in pharmaceutical research.

Kinase is an enzyme that adds phosphate groups to other molecules. This process is known as phosphorylation. Protein phosphorylation is a key aspect in the regulation of a large number of cellular processes including cellular division, metabolism, signal transduction, and so on. There are over 500 kinases encoded by the human genome and it has been estimated that kinases regulate approximately 50% of cellular functions. Kinases are a large group of drug targets in drug discovery. Kinase inhibitors are an important class of drugs that block certain enzymes involved in diseases such as cancer and inflammatory disorders.

Kinase inhibitor library designed by MCE contains 3,998 kinase inhibitors and regulators mainly targeting protein kinases (VEGFR, EGFR, BTK, CDK, Akt, etc.), lipid kinases (PI3K, PI4K, SK, etc.) and carbohydrate kinases (Hexokinase), and is a useful tool for kinase drug discovery and related research.

Adult stem cells are important for tissue homeostasis and regeneration due to their ability to self-renew and generate multiple types of differentiated daughters. Self-renewal is reflected by their capacity to undergo multiple/limitless divisions. Several signaling pathways are involved in self-renewal of stem cells, that is, Notch, Wnt, and Hedgehog pathways or Polycomb family proteins. Recent studies mainly focus on cancer stem cell (CSCs), induced pluripotent stem cell (iPSCs), neural stem cell and maintenance of embryonic stem cell pluripotency. Among them, CSCs have been believed to be responsible for tumor initiation, growth, and recurrence that have implications for cancer therapy.

MCE owns a unique collection of 2,931 compounds that can be used for stem cell regulatory and signaling pathway research.

GPCRs are a large family of cell surface receptors that respond to a variety of external signals. Binding of a signaling molecule to a GPCR results in G protein activation, which in turn triggers the production of any number of second messengers. GPCRs play an important role in the human body, and increased understanding of these receptors has greatly affected modern medicine. In fact, researchers estimate that between one-third to one-half of all approved drugs act by binding to GPCRs. GPCRs are a large group of drug targets in drug discovery.

MCE provides a unique collection of 3,519 small molecules targeting GPCRs that can be used in the screening for various GPCRs-related research and drug development projects.