Wednesday, July 25, 2018
Mechanistic Insight through Irreversible Inhibition: DNA Polymerase θ Uses a Common Active Site for Polymerase and Lyase Activities
Daniel J. Laverty, Ifor P. Mortimer, and Marc M. Greenberg
J. Am. Chem. Soc. 2018 140 (29), 9034–9037
DNA polymerase θ (Pol θ) is a multifunctional enzyme. It is nonessential in normal cells, but its upregulation in cancer cells correlates with cellular resistance to oxidative damage and poor prognosis. Pol θ possesses polymerase activity and poorly characterized lyase activity. We examined the Pol θ lyase activity on various abasic sites and determined that the enzyme is inactivated upon attempted removal of the oxidized abasic site commonly associated with C4′-oxidation (pC4-AP). Covalent modification of Pol θ by the DNA lesion enabled determination of the primary nucleophile (Lys2383) responsible for Schiff base formation in the lyase reaction. Unlike some other base excision repair polymerases, Pol θ uses a single active site for polymerase and lyase activity. Mutation of Lys2383 significantly reduces both enzyme activities but not DNA binding. Demonstration that Lys2383 is required for polymerase and lyase activities indicates that this residue is an Achilles heel for Pol θ and suggests a path forward for designing inhibitors of this attractive anticancer target.
Discovery and Characterization of a Novel Series of Chloropyrimidines as Covalent Inhibitors of the Kinase MSK1
Adrian Hall, Jan Abendroth, Madison J. Bolejack, Tom Ceska, Sylvie Dell’Aiera, Victoria Ellis, David Fox, Cyril François, Muigai M. Muruthi,...
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Discovery of Non-Cysteine-Targeting Covalent Inhibitors by Activity-Based Proteomic Screening with a Cysteine-Reactive ProbeYejin Jung, Naotaka Noda, Junichiro Takaya, Masahiro Abo, Kohei Toh, Ken Tajiri, Changyi Cui, Lu Zhou, Shin-ichi Sato, and Motonari Uesugi A...
Discovery of M-1121 as an Orally Active Covalent Inhibitor of Menin-MLL Interaction Capable of Achieving Complete and Long-Lasting Tumor RegressionMeng Zhang, Angelo Aguilar, Shilin Xu, Liyue Huang, Krishnapriya Chinnaswamy, Taryn Sleger, Bo Wang, Stefan Gross, Brandon N. Nicolay, Sebas...