MB-3   Click here for help

GtoPdb Ligand ID: 8393

Synonyms: α-methylene-γ-butyrolactone 3
Compound class: Synthetic organic
Comment: MB-3 is reported as a cell-permeable small-molecule inhibitor of the histone acetyltransferase enzyme, general control nonderepressible 5 (GCN5, gene symbol KAT2B) [1]. In vitro, MB-3 has been shown to inhibit GCN5-driven acetylation of the chimeric oncoprotein E2A-PBX1 [4]. E2A-PBX1 is a non-histone target of GCN5 [5].
A 2017 article by Dahlin et al. suggests that the thiol-reactivity of MB-3 brings in to question its activity as a selective HAT inhibitor [3].
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Ligand Activity Visualisation Charts

These are box plot that provide a unique visualisation, summarising all the activity data for a ligand taken from ChEMBL and GtoPdb across multiple targets and species. Click on a plot to see the median, interquartile range, low and high data points. A value of zero indicates that no data are available. A separate chart is created for each target, and where possible the algorithm tries to merge ChEMBL and GtoPdb targets by matching them on name and UniProt accession, for each available species. However, please note that inconsistency in naming of targets may lead to data for the same target being reported across multiple charts.

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View interactive charts of activity data across species
2D Structure
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2D Structure

An image of the ligand's 2D structure. For small molecules with SMILES these are drawn using the NCI/CADD Chemical Identifier Resolver. Click on the image to access the chemical structure search tool with the ligand pre-loaded in the structure editor. For other types of ligands, e.g. longer nucleotides and peptides, a manually drawn representation of the molecule may be provided.

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Physico-chemical Properties
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Physico-chemical Properties

Calculated molecular properties are available for small molecules and natural products (not peptides). Properties were generated using the CDK toolkit. All properties were selected to enable the prediction of the Lipinski Rule-of-Five profile or ‘druglikeness’ for each ligand. For more info on each category see the help pages.

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Hydrogen bond acceptors 5
Hydrogen bond donors 1
Rotatable bonds 3
Topological polar surface area 80.67
Molecular weight 186.05
XLogP 0.49
No. Lipinski's rules broken 0
SMILES / InChI / InChIKey
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SMILES / InChI / InChIKey

SMILES (Simplified Molecular Input Line Entry Specification) A specification for unambiguously describing the structure of chemical molecules using short ASCII strings. Canonical SMILES specify a unique representation of the 2D structure without chiral or isotopic specifications. Isomeric SMILES include chiral specification and isotopes.

Standard InChI (IUPAC International Chemical Identifier) and InChIKey InChI is a non-proprietary, standard, textual identifier for chemical substances designed to facilitate linking of information and database searching. An InChIKey is a simplified version of a full InChI, designed for easier web searching.

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Canonical SMILES CCCC1OC(=O)C(=O)C1C(=O)O
Isomeric SMILES CCC[C@@H]1OC(=O)C(=O)[C@H]1C(=O)O
InChI InChI=1S/C8H10O5/c1-2-3-4-5(7(10)11)6(9)8(12)13-4/h4-5H,2-3H2,1H3,(H,10,11)/t4-,5-/m0/s1
InChI Key AKWJFOMNTDKSRR-WHFBIAKZSA-N
No information available.
Mechanism Of Action and Pharmacodynamic Effects Click here for help
E2A-PBX1 (pre-B-cell leukemia transcription factor) is a fused oncoprotein which results from a t(1;19)(q23;q13) chromosomal translocation. E2A-PBX1 is found in more than 20% of patients with pediatric pre-B ALL (acute lymphoblastic leukemia) [2]. GCN5-induced acetylation of E2A-PBX1 stablises the oncoprotein and leads to oncogenic transformation in B-cells. MB-3 inhibits this process and results in increased E2A-PBX1 degradation via a E3 ubiquitin ligase HDM2 mechanism [4].