Sortase-Catalyzed Initiator Attachment Enables High Yield Growth of a Stealth Polymer from the C Terminus of a Protein
Conventional methods for synthesizing protein/peptide-polymer conjugates, as a means to improve the pharmacological properties of therapeutic biomolecules, typically have drawbacks including low yield, non-trivial separation of conjugates from reactants, and lack of site- specificity, which results in heterogeneous products with significantly compromised bioactivity. To address these limitations, the use of sortase A from Staphylococcus aureus is demonstrated to site-specifically attach an initiator solely at the C-terminus of green fluorescent protein (GFP), followed by in situ growth of a stealth polymer, poly(oligo(ethylene glycol) methyl ether methacrylate) by atom transfer radical polymerization (ATRP). Sortase-catalyzed initiator attachment proceeds with high specificity and near-complete (≈95%) product conversion. Subsequent in situ ATRP in aqueous buffer produces 1:1 stoichiometric conjugates with >90% yield, low dispersity, and no denaturation of the protein. This approach introduces a simple and useful method for high yield synthesis of protein/peptide-polymer conjugates. A general method is developed for the high-yield synthesis of C-terminally site-specific and one-to-one stoichiometric protein/peptide-polymer conjugates. Sortase A from Staphylococcus aureus is used to site-specifically attach an initiator solely at the C-terminus of green fluorescent protein, followed by in situ growth of a stealth polymer, poly(oligo(ethylene glycol) methyl ether methacrylate) by atom transfer radical polymerization. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Qi, Y; Amiram, M; Gao, W; McCafferty, DG; Chilkoti, A
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