Improved Electrophile Design for Exquisite Covalent Molecule Selectivity
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ABSTRACT: Using chemical proteomic techniques, we demonstrate that elaboration of the electrophile to a tert-Butyl (t-Bu) fumarate ester significantly decreases time-dependent off-target reactivity and abolishes time-independent off-target reactivity but retains BTK target engagement. While an alkyne-bearing probe analog of Ibrutinib has 247 protein targets, our t-Bu fumarate Ibrutinib probe analog has only 7 protein targets. Of these 7 targets, BTK is the only time-independent target. This increase in selectivity is also conferred to the t-Bu inhibitor itself, reducing off-targets by 70%.. By shotgun proteomics, we investigated the consequences of treatment with Ibrutinib and our t-Bu analog and discovered that only 8 proteins are downregulated in response to treatment with the t-Bu analog compared to 107 with Ibrutinib. Of these 8 proteins, 7 are also downregulated by Ibrutinib and a majority of these targets are associated with BTK biology. Taken together, these findings reveal a previously-unappreciated opportunity to increase cysteine-reactive covalent inhibitor selectivity through electrophilic structure optimization
INSTRUMENT(S): timsTOF Pro
ORGANISM(S): Homo Sapiens (ncbitaxon:9606)
SUBMITTER: Balyn Zaro
PROVIDER: MSV000089155 | MassIVE | Tue Mar 29 21:16:00 BST 2022
REPOSITORIES: MassIVE
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