Hefei KS-V Peptide Biological Technology Co., Ltd.

We report here a robust and practical strategy for chemical protein synthesis using an o-nitrobenzyl group as a temporary protective group for an N-terminal cysteine residue of intermediate hydrazide fragments. By reinvestigating the photoremoval of an o-nitrobenzyl group, we establish a robust and reliable strategy for its quantitative photodeprotection. The o-nitrobenzyl group is completely stable to oxidative NaNO₂ treatment and has been applied to the convergent chemical synthesis of programmed death ligand 1 fragment, providing a practical avenue for hydrazide-based native chemical ligation.

We report a sortase-based site-specific antibody–drug conjugation strategy involving an affinity peptide-directed acyl transfer reaction and the sortase-mediated peptide ligation that allows for the attachment of protein-based payloads to antibodies.

A practical strategy for the total stepwise solid-phase synthesis of peptide–oligonucleotide conjugates was developed, which will expand the applicability of this strategy in the preparation of peptide–oligonucleotide conjugates.