6eq5
MTH1 in complex with fragment 4
Structural highlights
Function8ODP_HUMAN Antimutagenic. Acts as a sanitizing enzyme for oxidized nucleotide pools, thus suppressing cell dysfunction and death induced by oxidative stress. Hydrolyzes 8-oxo-dGTP, 8-oxo-dATP and 2-OH-dATP, thus preventing misincorporation of oxidized purine nucleoside triphosphates into DNA and subsequently preventing A:T to C:G and G:C to T:A transversions. Able to hydrolyze also the corresponding ribonucleotides, 2-OH-ATP, 8-oxo-GTP and 8-oxo-ATP.[1] [2] [3] [4] [5] Publication Abstract from PubMedThe DNA-repair enzyme MutT homolog 1 (MTH1) is a potential target for a broad range of tumors. Its substrate binding site features a non-catalytical pair of aspartic acids which resembles the catalytic dyad of aspartic proteases. We hypothesized that inhibitors of the latter might be re-targeted for MTH1 despite the two enzyme classes having different substrates and catalyze different reactions. We selected from the crystal structures of holo aspartic proteases a library of nearly 350 inhibitors for in silico screening. Three fragment hits were identified by docking and scoring according to a force field-based energy with continuum dielectric solvation. These fragments showed good ligand efficiency in a colorimetric assay (MW <300 Da and IC50<50muM). Molecular dynamics simulations were carried out for determining the most favorable interaction patterns. On the basis of the simulation results we evaluated in vitro seven commercially available compounds, two of which showed submicromolar potency for MTH1. To obtain definitive evidence of the predicted binding modes we solved the crystal structures of five of the 10 inhibitors predicted in silico. The final step of hit optimization was guided by protein crystallography and involved the synthesis of a single compound, the lead 11, which shows nanomolar affinity for MTH1 in two orthogonal binding assays, and selectivity higher than 2000-fold against its original target (BACE1). The high rate of fragment-hit identification and the fast optimization suggest that ligand retargeting by binding site analogy is an efficient strategy for drug design. Ligand retargeting by binding site analogy.,Wiedmer L, Scharer C, Spiliotopoulos D, Hurzeler M, Sledz P, Caflisch A Eur J Med Chem. 2019 Apr 25;175:107-113. doi: 10.1016/j.ejmech.2019.04.037. PMID:31077996[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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