title: Neutralizing peptide ligands selected from phage-displayed libraries mimic the conformational epitope on domain III of the Japanese encephalitis virus envelope protein.
abstract: The envelope (E) protein of Japanese encephalitis virus (JEV) contains 500 amino acids with six "conserved" disulfide bonds to maintain its conformational structure. Neutralizing epitopes located on the E protein are mostly conformational dependent. In this study, we used phage-displayed 12-residue combinatorial peptide libraries to select high-affinity peptide ligands bound to monoclonal antibody E3.3. The specific peptide ligands presented on ten high-affinity phage clones displayed six different amino acid sequences, all showing a novel cis-proline turn structure. After being superimposed onto the best fit of the three-dimensional structure of JEV E protein, these peptide structures were mapped to a conformational region constituted by three continuous polypeptide segments (E307-E309, E327-E333, E386-E390) in domain III. Synthetic peptide ligands based on one peptide sequence (E18) were further investigated using alanine scanning within the cis-proline turn structure to demonstrate its unique molecular characteristics. Our results showed that three residues forming the novel cis-proline turn structure were all important in eliciting JEV-specific neutralizing antibodies in mice.
authors.affiliation: Department of Life Science, National Tsing Hua University, 30013, Taiwan, Hsinchu, PR China.
authors.forename: S C
authors.initials: SC
authors.lastname: Wu
authors.forename: C W
authors.initials: CW
authors.lastname: Lin
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000276:immunology; D000956:Antigens, Viral / Q000737:chemistry / Q000276:immunology; D002522:Chlorocebus aethiops; D004664:Encephalitis Virus, Japanese / Q000737:chemistry / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D000939:Epitopes / Q000737:chemistry* / Q000276:immunology; D007114:Immunization; D008024:Ligands; D051379:Mice; D008807:Mice, Inbred BALB C; D008958:Models, Molecular; D018716:Molecular Mimicry; D009500:Neutralization Tests; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry* / Q000276:immunology*; D017434:Protein Structure, Tertiary; D014709:Vero Cells; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000276:immunology*; D010948:Viral Plaque Assay
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral; D000939:Epitopes; D008024:Ligands; D019151:Peptide Library; D010455:Peptides; D014759:Viral Envelope Proteins