Rapid Covalent-Probe Discovery by Electrophile-Fragment Screening.

Journal of the American Chemical Society (2019-05-08)
Efrat Resnick, Anthony Bradley, Jinrui Gan, Alice Douangamath, Tobias Krojer, Ritika Sethi, Paul P Geurink, Anthony Aimon, Gabriel Amitai, Dom Bellini, James Bennett, Michael Fairhead, Oleg Fedorov, Ronen Gabizon, Jin Gan, Jingxu Guo, Alexander Plotnikov, Nava Reznik, Gian Filippo Ruda, Laura Díaz-Sáez, Verena M Straub, Tamas Szommer, Srikannathasan Velupillai, Daniel Zaidman, Yanling Zhang, Alun R Coker, Christopher G Dowson, Haim M Barr, Chu Wang, Kilian V M Huber, Paul E Brennan, Huib Ovaa, Frank von Delft, Nir London

Covalent probes can display unmatched potency, selectivity, and duration of action; however, their discovery is challenging. In principle, fragments that can irreversibly bind their target can overcome the low affinity that limits reversible fragment screening, but such electrophilic fragments were considered nonselective and were rarely screened. We hypothesized that mild electrophiles might overcome the selectivity challenge and constructed a library of 993 mildly electrophilic fragments. We characterized this library by a new high-throughput thiol-reactivity assay and screened them against 10 cysteine-containing proteins. Highly reactive and promiscuous fragments were rare and could be easily eliminated. In contrast, we found hits for most targets. Combining our approach with high-throughput crystallography allowed rapid progression to potent and selective probes for two enzymes, the deubiquitinase OTUB2 and the pyrophosphatase NUDT7. No inhibitors were previously known for either. This study highlights the potential of electrophile-fragment screening as a practical and efficient tool for covalent-ligand discovery.

Product Number
Product Description

Nicotinamide (Niacinamide), analytical standard
S-(5′-Adenosyl)-L-methionine chloride dihydrochloride, ≥75%