title: Sortase-catalyzed initiator attachment enables high yield growth of a stealth polymer from the C terminus of a protein.
abstract: 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.
authors.affiliation: Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
authors.forename: Yizhi
authors.initials: Y
authors.lastname: Qi
authors.forename: Miriam
authors.initials: M
authors.lastname: Amiram
authors.forename: Weiping
authors.initials: W
authors.lastname: Gao
authors.forename: Dewey G
authors.initials: DG
authors.lastname: McCafferty
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Chilkoti
mesh_terms: D019881:Aminoacyltransferases / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D003546:Cysteine Endopeptidases / Q000737:chemistry*; D049452:Green Fluorescent Proteins / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D049452:Green Fluorescent Proteins; D011092:Polyethylene Glycols; D019881:Aminoacyltransferases; C120542:sortase A; D003546:Cysteine Endopeptidases
keywords: atom transfer radical polymerization (ATRP); biological application of polymers; grafting from; protein-polymer conjugates; sortase