title: Selection of high affinity ligands to hepatitis B core antigen from a phage-displayed cyclic peptide library.
abstract: M13 phages that display random disulfide constrained heptapeptides on their gpIII proteins were used to select for high affinity ligands to hepatitis B core antigen (HBcAg). Phages bearing the amino acid sequences C-WSFFSNI-C and C-WPFWGPW-C were isolated, and a binding assay in solution showed that these phages bind tightly to full-length and truncated HBcAg with K D rel values less than 25 nM, which is at least 10 orders of magnitude higher than phage carrying the peptide sequence LLGRMK selected from a linear peptide library. Both the phages that display the constrained peptides were inhibited from binding to HBcAg particles by a monoclonal antibody that binds specifically to the immunodominant region of the particles. A synthetic heptapeptide with the amino acid sequence WSFFSNI derived from one of the fusion peptides inhibits the binding of large surface antigen (L-HBsAg) to core particles with an IC50 value of 12 +/- 2 microM. This study has identified a smaller peptide with a greater inhibitory effect on L-HBsAg-HBcAg association.
authors.affiliation: Department of Biochemistry and Microbiology, Faculty of Science and Environmental Studies, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
authors.forename: Kok Lian
authors.initials: KL
authors.lastname: Ho
authors.forename: Khatijah
authors.initials: K
authors.lastname: Yusoff
authors.forename: Heng Fong
authors.initials: HF
authors.lastname: Seow
authors.forename: Wen Siang
authors.initials: WS
authors.lastname: Tan
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D000915:Antibody Affinity; D000937:Antigen-Antibody Reactions; D001435:Bacteriophages / Q000378:metabolism; D001665:Binding Sites; D006512:Hepatitis B Core Antigens / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D006514:Hepatitis B Surface Antigens / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D006515:Hepatitis B virus / Q000378:metabolism; D008024:Ligands; D008854:Microscopy, Electron; D019151:Peptide Library; D010456:Peptides, Cyclic / Q000302:isolation & purification / Q000378:metabolism*; D014176:Protein Biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D000911:Antibodies, Monoclonal; D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens; D008024:Ligands; D019151:Peptide Library; D010456:Peptides, Cyclic; D011994:Recombinant Proteins