1. Neolymphostin A Is a Covalent Phosphoinositide 3-Kinase (PI3K)/Mammalian Target of Rapamycin (mTOR) Dual Inhibitor That Employs an Unusual Electrophilic Vinylogous Ester.
- Author
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Castro-Falcón G, Seiler GS, Demir Ö, Rathinaswamy MK, Hamelin D, Hoffmann RM, Makowski SL, Letzel AC, Field SJ, Burke JE, Amaro RE, and Hughes CC
- Subjects
- Enzyme Inhibitors metabolism, Molecular Docking Simulation, Phosphatidylinositol 3-Kinases chemistry, Phosphatidylinositol 3-Kinases metabolism, Protein Conformation, Quinolines metabolism, Enzyme Inhibitors chemistry, Enzyme Inhibitors pharmacology, Esters chemistry, Phosphoinositide-3 Kinase Inhibitors, Quinolines chemistry, Quinolines pharmacology, TOR Serine-Threonine Kinases antagonists & inhibitors
- Abstract
Using a novel chemistry-based assay for identifying electrophilic natural products in unprocessed extracts, we identified the PI3-kinase/mTOR dual inhibitor neolymphostin A from Salinispora arenicola CNY-486. The method further showed that the vinylogous ester substituent on the neolymphostin core was the exact site for enzyme conjugation. Tandem MS/MS experiments on PI3Kα treated with the inhibitor revealed that neolymphostin covalently modified Lys802 with a shift in mass of +306 amu, corresponding to addition of the inhibitor and elimination of methanol. The binding pose of the inhibitor bound to PI3Kα was modeled, and hydrogen-deuterium exchange mass spectrometry experiments supported this model. Against a panel of kinases, neolymphostin showed good selectivity for PI3-kinase and mTOR. In addition, the natural product blocked AKT phosphorylation in live cells with an IC
50 of ∼3 nM. Taken together, neolymphostin is the first reported example of a covalent kinase inhibitor from the bacterial domain of life.- Published
- 2018
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