Disulfide bridge based conjugation of peptides to RAFT polymers

The reaction between bisulfones and the disulfide bridge of peptides or proteins allows the efficient bioconjugation without the loss of biological activity, which is often based on the three-dimensional structure of the biomolecule. This concept has been successfully applied using low molecular weight model compounds and PEG. In this article, RAFT polymers were postmodified to introduce bisulfone end-functionalities. This general approach has been tested here using poly(N-vinylpyrrolidone) PVP, which was prepared via RAFT polymerization. RAFT endgroup removal, followed by the reaction with divinyl sulfone and the bisulfone linker led to a disulfide reactive polymer. NMR studies, MALDI-TOF MSMS and SDS-PAGE confirm the successful reaction between somatostatin, a cyclic hormone peptide and the end-functionalized PVP. The RAFT process as a source to potential polymers widens the scope of this bioconjugation technique to a large array of potential structures.