Selective N-Terminal Acylation of Peptides and Proteins with Tunable Phenol Esters.
Jesper H MikkelsenMagnus B F GustafssonTroels SkrydstrupKim B JensenPublished in: Bioconjugate chemistry (2022)
Selective modification of peptides and proteins is of foremost importance for the development of biopharmaceuticals and exploring biochemical pathways, as well as other applications. Here, we present a study on the development of a general and easily applicable selective method for N -terminal acylation of biomolecules, applying a new type of phenol esters. Key to the success was the development of highly tunable phenol activators bearing in the ortho-position, sulfonic acid or sulfonamide, acting as a steric shield for hydrolysis, and electron-withdrawing groups in the other ortho- and para-position for controlling the reactivity of the activated phenol esters. A library of heptapeptides, testing all 20 natural amino acids positioned at the N -terminal, were acylated in a selective manner at the N -terminus. The majority showed high conversion and excellent N α -selectivity. Several biologically relevant biomolecules, including DesB30 insulin and human growth hormone, could also be modified at the N -terminal in a highly selective way, exemplified by either a fluorophore or a fatty acid sidechain. Finally, taking advantage of the possibility to accurately adjust the reactivity of the phenol esters, we present a potential strategy for the construction of dual active biopharmaceuticals through the employment of a bifunctional acylation linker and demonstrate its use in the creation of a GLP-1 insulin analogue, coupled through the lysine residue of GLP-1 and the N -terminal Phe B1 amine of DesB30 insulin.