Synthetic antibodies from a four-amino-acid code: a dominant role for tyrosine in antigen recognition.

ABSTRACT: Antigen-binding fragments (Fabs) with synthetic antigen-binding sites were isolated from phage-displayed libraries with restricted complementarity-determining region (CDR) diversity. Libraries were constructed such that solvent-accessible CDR positions were randomized with a degenerate codon that encoded for only four amino acids (tyrosine, alanine, aspartate, and serine). Nonetheless, high-affinity Fabs (K(d) = 2-10 nM) were isolated against human vascular endothelial growth factor (hVEGF), and the crystal structures were determined for two distinct Fab-hVEGF complexes. The structures revealed that antigen recognition was mediated primarily by tyrosine side chains, which accounted for 71% of the Fab surface area that became buried upon binding to hVEGF. In contrast, aspartate residues wit

SUBMITTER: Fellouse FA 

PROVIDER: S-EPMC515084 | biostudies-literature | 2004 Aug

REPOSITORIES: biostudies-literature