title: Genetically encoded initiator for polymer growth from proteins.
abstract: Despite the importance of protein-polymer bioconjugates, there is no general method for producing homogeneous recombinant protein that contains polymer initiators at defined sites. To address this deficiency, we designed the amino acid 4-(2'-bromoisobutyramido)phenylalanine (1) as an initiator in atom-transfer radical polymerization (ATRP) that would provide a stable linkage between the protein and growing polymer. We synthesized 1 and evolved a Methanococcus jannaschii tyrosyl-tRNA synthetase/tRNA(CUA) pair to genetically encode this initiator in response to an amber codon. To demonstrate the utility of this initiator, we produced green fluorescent protein (GFP) with 1 site-specifically incorporated on its surface (GFP-1). Purified GFP-1 was then used as an initiator under standard ATRP conditions with a monomer, oligo(ethylene oxide) monomethyl ether methacrylate, efficiently producing a polymer-GFP bioconjugate where the polymer is connected at our selected site on GFP.
authors.affiliation: Department of Chemistry, Franklin & Marshall College, Lancaster, Pennsylvania 17604-3003, USA.
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Peeler
authors.forename: Bradley F
authors.initials: BF
authors.lastname: Woodman
authors.forename: Saadyah
authors.initials: S
authors.lastname: Averick
authors.forename: Shigeki J
authors.initials: SJ
authors.lastname: Miyake-Stoner
authors.forename: Audrey L
authors.initials: AL
authors.lastname: Stokes
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Hess
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Matyjaszewski
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Mehl
mesh_terms: D001704:Biopolymers / Q000737:chemistry; D049452:Green Fluorescent Proteins / Q000737:chemistry*; D017017:Methanococcus / Q000201:enzymology*; D015394:Molecular Structure; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry; D013499:Surface Properties; D014448:Tyrosine-tRNA Ligase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: C555111:4-(2'-bromoisobutyroamido)phenylalanine; D001704:Biopolymers; D049452:Green Fluorescent Proteins; D010649:Phenylalanine; D014448:Tyrosine-tRNA Ligase