title: Reversible covalent inhibition of eEF-2K by carbonitriles.
abstract: eEF-2K is a potential target for treating cancer. However, potent specific inhibitors for this enzyme are lacking. Previously, we identified 2,6-diamino-4-(2-fluorophenyl)-4H-thiopyran-3,5-dicarbonitrile (DFTD) as an inhibitor of eEF-2K. Here we describe its mechanism of action against eEF-2K, on the basis of kinetic, mutational, and docking studies, and use chemoinformatic approaches to identify a similar class of carbonitrile-containing compounds that exhibit the same mechanism of action. We show that DFTD behaves as a reversible covalent inhibitor of eEF-2K with a two-step mechanism of inhibition: a fast initial binding step, followed by a slower reversible inactivation step. Molecular docking suggests that a nitrile group of DFTD binds within 4.5 Å of the active site Cys146 to form a reversible thioimidate adduct. Because Cys146 is not conserved amongst other related kinases, targeting this residue holds promise for the development of selective covalent inhibitors of eEF-2K.
authors.affiliation: Texas Screening Alliance for Cancer Therapeutics, The University of Texas at Austin, 105 E. 24th Street, Stop A5300, Austin, TX 78712 (USA).
authors.forename: Ashwini K
authors.initials: AK
authors.lastname: Devkota
authors.forename: Ramakrishna
authors.initials: R
authors.lastname: Edupuganti
authors.forename: Chunli
authors.initials: C
authors.lastname: Yan
authors.forename: Yue
authors.initials: Y
authors.lastname: Shi
authors.forename: Jiney
authors.initials: J
authors.lastname: Jose
authors.forename: Qiantao
authors.initials: Q
authors.lastname: Wang
authors.forename: Tamer S
authors.initials: TS
authors.lastname: Kaoud
authors.forename: Eun Jeong
authors.initials: EJ
authors.lastname: Cho
authors.forename: Pengyu
authors.initials: P
authors.lastname: Ren
authors.forename: Kevin N
authors.initials: KN
authors.lastname: Dalby
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D020134:Catalytic Domain; D054736:Elongation Factor 2 Kinase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D062105:Molecular Docking Simulation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009570:Nitriles / Q000737:chemistry* / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment
chemical_list: D009570:Nitriles; D011994:Recombinant Proteins; D054736:Elongation Factor 2 Kinase
keywords: cancer; covalent inhibitors; drug discovery; eEF-2 kinase; nitriles