Sunday, December 15, 2019

Kinetic Optimization of Lysine-Targeting Covalent Inhibitors of HSP72

Jonathan PettingerMichael CarterKeith Jones, and Matthew D. Cheeseman
Journal of Medicinal Chemistry 2019
DOI: 10.1021/acs.jmedchem.9b01709

The covalent inhibition mechanism of action, which overcomes competition with high-affinity, high-abundance substrates of challenging protein targets, can deliver effective chemical probes and drugs. The success of this strategy has centered on exposed cysteine residues as nucleophiles but the low abundance of cysteine in the proteome has limited its application. We have recently reported our discovery that lysine-56 in the difficult-to-drug target HSP72 could form a covalent bond with a small-molecule inhibitor. We now disclose the optimization of these targeted covalent inhibitors using rational design. Essential to our optimization was the development of a new covalent fluorescence polarization assay, which allows for the direct measurement of the key kinetic parameter in covalent inhibitor design, kinact/KI, extrapolation of the underlying parameters, kinact and Ki, and direct comparison to reversible analogues. Using our approach, we demonstrate a >100-fold enhancement in covalent efficiency and key learnings in lysine-selective electrophile optimization.

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Oncogenic KRAS G12C: Kinetic and Redox Characterization of Covalent Inhibition

Minh V. Huynh, Derek Parsonage, Tom E. Forshaw, Venkat R. Chirasani, G. Aaron Hobbs, Hanzhi Wu, Jingyun Lee, Cristina M. Furdui, Leslie B. P...