title: Direct polymerization of proteins.
abstract: We report the synthesis of active polymers of superfolder green fluorescent protein (sfGFP) in one step using Click chemistry. Up to six copies of the non-natural amino acids (nnAAs) p-azido-l-phenylalanine (pAzF) or p-propargyloxy-l-phenylalanine (pPaF) were site-specifically inserted into sfGFP by cell-free protein synthesis (CFPS). sfGFP containing two or three copies of these nnAAs were coupled by copper-catalyzed azide-alkyne cycloaddition to synthesize linear or branched protein polymers, respectively. The protein polymers retained ≥63% of their specific activity (i.e., fluorescence) after coupling. Polymerization of a concentrated solution of triply substituted sfGFP resulted in fluorescent macromolecular particles. Our method can be generalized to synthesize polymers of a protein or copolymers of any two or more proteins, and the conjugation sites can be determined exactly by standard genetic manipulation. Polymers of proteins and small molecules can also be created with this technology to make a new class of scaffolds or biomaterials.
authors.affiliation: Department of Chemical Engineering, Stanford University , 381 North-South Mall, Stanford, California 94305, United States.
authors.forename: Cem
authors.initials: C
authors.lastname: Albayrak
authors.forename: James R
authors.initials: JR
authors.lastname: Swartz
mesh_terms: D000480:Alkynes; D001386:Azides / Q000737:chemistry; D001672:Biocompatible Materials / Q000138:chemical synthesis; D057930:Click Chemistry / Q000379:methods*; D003300:Copper; D049452:Green Fluorescent Proteins / Q000138:chemical synthesis*; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000737:chemistry; D055503:Protein Multimerization
chemical_list: C549407:4-propargyloxyphenylalanine; D000480:Alkynes; D001386:Azides; D001672:Biocompatible Materials; D049452:Green Fluorescent Proteins; C027162:4-azidophenylalanine; D010649:Phenylalanine; D003300:Copper