title: Trinucleotide cassettes increase diversity of T7 phage-displayed peptide library.
abstract: BACKGROUND
  Amino acid sequence diversity is introduced into a phage-displayed peptide library by randomizing library oligonucleotide DNA. We recently evaluated the diversity of peptide libraries displayed on T7 lytic phage and M13 filamentous phage and showed that T7 phage can display a more diverse amino acid sequence repertoire due to differing processes of viral morphogenesis.
  
  
  METHODS
  In this study, we evaluated and compared the diversity of a 12-mer T7 phage-displayed peptide library randomized using codon-corrected trinucleotide cassettes with a T7 and an M13 12-mer phage-displayed peptide library constructed using the degenerate codon randomization method.
  
  
  RESULTS
  We herein demonstrate that the combination of trinucleotide cassette amino acid codon randomization and T7 phage display construction methods resulted in a significant enhancement to the functional diversity of a 12-mer peptide library. This novel library exhibited superior amino acid uniformity and order-of-magnitude increases in amino acid sequence diversity as compared to degenerate codon randomized peptide libraries. Comparative analyses of the biophysical characteristics of the 12-mer peptide libraries revealed the trinucleotide cassette-randomized library to be a unique resource.
  
  
  CONCLUSIONS
  The combination of T7 phage display and trinucleotide cassette randomization resulted in a novel resource for the potential isolation of binding peptides for new and previously studied molecular targets.
authors.affiliation: Molecular Targets Development Program, Center for Cancer Research, NCI-Frederick, Frederick, Maryland 21702, USA. lhaugh@ncifcrf.gov
authors.forename: Lauren R H
authors.initials: LR
authors.lastname: Krumpe
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Schumacher
authors.forename: James B
authors.initials: JB
authors.lastname: McMahon
authors.forename: Lee
authors.initials: L
authors.lastname: Makowski
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Mori
mesh_terms: D000595:Amino Acid Sequence; D017104:Bacteriophage M13; D017123:Bacteriophage T7 / Q000235:genetics*; D014644:Genetic Variation; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional / Q000235:genetics*; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification; D019809:Streptavidin / Q000378:metabolism; D018911:Trinucleotide Repeats / Q000235:genetics*
chemical_list: D019151:Peptide Library; D010455:Peptides; D019809:Streptavidin