title: Self-Assembly of Temperature-Responsive Protein-Polymer Bioconjugates.
abstract: We report a simple temperature-responsive bioconjugate system comprising superfolder green fluorescent protein (sfGFP) decorated with poly[(oligo ethylene glycol) methyl ether methacrylate] (PEGMA) polymers. We used amber suppression to site-specifically incorporate the non-canonical azide-functional amino acid p-azidophenylalanine (pAzF) into sfGFP at different positions. The azide moiety on modified sfGFP was then coupled using copper-catalyzed "click" chemistry with the alkyne terminus of a PEGMA synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. The protein in the resulting bioconjugate was found to remain functionally active (i.e., fluorescent) after conjugation. Turbidity measurements revealed that the point of attachment of the polymer onto the protein scaffold has an impact on the thermoresponsive behavior of the resultant bioconjugate. Furthermore, small-angle X-ray scattering analysis showed the wrapping of the polymer around the protein in a temperature-dependent fashion. Our work demonstrates that standard genetic manipulation combined with an expanded genetic code provides an easy way to construct functional hybrid biomaterials where the location of the conjugation site on the protein plays an important role in determining material properties. We anticipate that our approach could be generalized for the synthesis of complex functional materials with precisely defined domain orientation, connectivity, and composition.
authors.affiliation: Department of Chemistry, University of Warwick , Gibbet Hill Road, Coventry CV4 7AL, United Kingdom.
authors.forename: Dafni
authors.initials: D
authors.lastname: Moatsou
authors.affiliation: Department of Chemical and Biological Engineering, Chemistry of Life Processes Institute, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Jian
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Chemical and Biological Engineering, Chemistry of Life Processes Institute, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Arnaz
authors.initials: A
authors.lastname: Ranji
authors.affiliation: Department of Chemistry, University of Warwick , Gibbet Hill Road, Coventry CV4 7AL, United Kingdom.
authors.forename: Anaïs
authors.initials: A
authors.lastname: Pitto-Barry
authors.affiliation: Department of Chemical and Biological Engineering, Chemistry of Life Processes Institute, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Ioanna
authors.initials: I
authors.lastname: Ntai
authors.affiliation: Department of Chemical and Biological Engineering, Chemistry of Life Processes Institute, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Jewett
authors.affiliation: Department of Chemistry, University of Warwick , Gibbet Hill Road, Coventry CV4 7AL, United Kingdom.
authors.forename: Rachel K
authors.initials: RK
authors.lastname: O'Reilly
mesh_terms: D001386:Azides / Q000737:chemistry; D049452:Green Fluorescent Proteins / Q000737:chemistry*; D057446:Hydrodynamics; D008689:Methacrylates / Q000737:chemistry*; D008958:Models, Molecular; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D011487:Protein Conformation; D013696:Temperature
chemical_list: D001386:Azides; D008689:Methacrylates; C524499:polyethylene glycol methacrylate; D049452:Green Fluorescent Proteins; C027162:4-azidophenylalanine; D011092:Polyethylene Glycols; D010649:Phenylalanine