Efficient Amino-Sulfhydryl Stapling on Peptides and Proteins Using Bifunctional NHS-Activated Acrylamides

Widely used reagents in the peptide functionalization toolbox, Michael acceptors and N-hydroxysuccinimide (NHS) activated esters, are combined in NHS-activated acrylamides for efficient chemoselective amino-sulfhydryl stapling on native peptides and proteins. NHS-activated acrylamides allow for a fast functionalization of N-terminal cysteines (k(2)=1.54 +/- 0.18x10(3) M-1 s(-1)) under dilute aqueous conditions, enabling selectivity over other nucleophilic amino acids. Additionally, the versatility of these new bioconjugation handles was demonstrated in the cross-linking of in-chain or C-terminal cysteines with nearby lysine residues. NHS-activated acrylamides are compatible with the use of other cysteine selective reagents, allowing for orthogonal dual-modifications. This strategy was successfully applied to the late-stage functionalization of peptides and proteins with a PEG unit, fluorescent probe, and cytotoxic agent. The level of molecular control offered by NHS-activated acrylamides is expected to promote amino-sulfhydryl stapling technology as a powerful strategy to design functional bioconjugates.

Automated summary

NHS-activated acrylamides, combining Michael acceptors and NHS activated esters, offer fast and chemoselective amino-sulfhydryl stapling on peptides and proteins under aqueous conditions, showing versatility and compatibility with other cysteine selective reagents for orthogonal dual-modifications. This strategy allows for late-stage functionalization of bioconjugates with various molecules, demonstrating a powerful tool in designing functional peptides and proteins.