Orthosteric inhibition of MutSβ ATPase function: First disclosure of MSH3-bound small molecule inhibitors

Orthosteric inhibitors of the human heterodimeric DNA mismatch repair complex MutSβ were identified by high-throughput screening. Following extensive hit confirmation to remove false positives, two series were found to give consistent activity free of likely artefactual effects. Extensive hit profiling confirmed an ATP-competitive mode of action and resulted in our obtaining the first reported X-ray and cryo-EM structures of small molecule inhibitors of MutSβ occupying the ATP-binding site of MSH3.