Mimicking of discontinuous epitopes by phage-displayed peptides, I. Epitope mapping of human H ferritin using a phage library of constrained peptides

摘要: Abstract We have constructed a random nonapeptide library in the N-terminal region of major coat protein VIII bacteriophage f1, with two cysteines flanking insert, and preliminary data suggest that many clones display at least some their peptides cyclized form. This was used to select oligopeptides binding monoclonal antibody (mAb) H 107, recognising assembled native conformation recombinant human H-subunit ferritin (H Fer), whose three-dimensional structure is known. Comparison selected one another allowed us derive consensus sequences characterized by conserved amino acid (aa) residues. Analysis distribution aa side chains exposed on surface Fer reveals most defining both are present either end big loop or A helix. These regions Fer, though separated linear sequence, very close folded molecule. Interestingly, each sequence derived from phage-displayed good candidates for mimicry therefore constituting part H107 epitope. To provide support this hypothesis, we several mutants carrying point mutations different positions these regions. The did not affect assembly reactivity mAb, but greatly reduced abolished mAb. results indicate discontinuous epitope necessary binding.