A Recombinant Approach For Stapled Peptide Discovery Yields Inhibitors of the RAD51 Recombinase

Abstract

Stapling is a macrocyclisation method that connects amino acid side chains of a peptide to improve its pharmacological properties. We describe an approach for stapled peptide preparation and biochemical evaluation that combines recombinant expression of fusion constructs of target peptides and cysteine-reactive divinylheteroaryl chemistry, as an alternative to solid-phase synthesis. We then employ this workflow to prepare and evaluate BRC-repeatderived inhibitors of the RAD51 recombinase, showing that a diverse range of secondary structure elements in the BRC repeat can be stapled without compromising binding and function. Using X-ray crystallography, we elucidate the atomic-level features of the staple moieties.