title: Protein evolution with an expanded genetic code.
abstract: We have devised a phage display system in which an expanded genetic code is available for directed evolution. This system allows selection to yield proteins containing unnatural amino acids should such sequences functionally outperform ones containing only the 20 canonical amino acids. We have optimized this system for use with several unnatural amino acids and provide a demonstration of its utility through the selection of anti-gp120 antibodies. One such phage-displayed antibody, selected from a naïve germline scFv antibody library in which six residues in V(H) CDR3 were randomized, contains sulfotyrosine and binds gp120 more effectively than a similarly displayed known sulfated antibody isolated from human serum. These experiments suggest that an expanded "synthetic" genetic code can confer a selective advantage in the directed evolution of proteins with specific properties.
authors.affiliation: Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
authors.forename: Chang C
authors.initials: CC
authors.lastname: Liu
authors.forename: Antha V
authors.initials: AV
authors.lastname: Mack
authors.forename: Meng-Lin
authors.initials: ML
authors.lastname: Tsao
authors.forename: Jeremy H
authors.initials: JH
authors.lastname: Mills
authors.forename: Hyun Soo
authors.initials: HS
authors.lastname: Lee
authors.forename: Hyeryun
authors.initials: H
authors.lastname: Choe
authors.forename: Michael
authors.initials: M
authors.lastname: Farzan
authors.forename: Peter G
authors.initials: PG
authors.lastname: Schultz
authors.forename: Vaughn V
authors.initials: VV
authors.lastname: Smider
mesh_terms: D000596:Amino Acids / Q000235:genetics; D000914:Antibodies, Viral / Q000276:immunology; D019020:Directed Molecular Evolution; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli; D005815:Genetic Code; D005822:Genetic Vectors; D005854:Germ Cells / Q000276:immunology; D006678:HIV / Q000276:immunology; D015699:HIV Envelope Protein gp120 / Q000276:immunology; D006801:Humans; D019151:Peptide Library; D011506:Proteins / Q000235:genetics*; D020539:Sequence Analysis, Protein; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D000596:Amino Acids; D000914:Antibodies, Viral; D015699:HIV Envelope Protein gp120; D019151:Peptide Library; D011506:Proteins; C005662:tyrosine O-sulfate; D014443:Tyrosine