Protein evolution with an expanded genetic code.
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.
Liu
Chang C
CC
Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Mack
Antha V
AV
Tsao
Meng-Lin
ML
Mills
Jeremy H
JH
Lee
Hyun Soo
HS
Choe
Hyeryun
H
Farzan
Michael
M
Schultz
Peter G
PG
Smider
Vaughn V
VV
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
D000596:Amino Acids; D000914:Antibodies, Viral; D015699:HIV Envelope Protein gp120; D019151:Peptide Library; D011506:Proteins; C005662:tyrosine O-sulfate; D014443:Tyrosine