A conformational epitope mapped in the bovine herpesvirus type 1 envelope glycoprotein B by phage display and the HSV-1 3D structure

•Homologous protein was used as a target for structural alignment with a mimetic peptide.•Conformational new discontinuous epitope was mapped on BoHV-1 Env gB protein.•Phage displayed peptide as a useful tool for BoHV-1 diagnosis.•The strategy described can be used to uncover epitopes for theranostic applications.

The selected dodecapeptide 1DRALYGPTVIDH12 from a phage-displayed peptide library and the crystal structure of the envelope glycoprotein B (Env gB) from Herpes Simplex Virus type 1 (HSV-1) led us to the identification of a new discontinuous epitope on the Bovine herpesvirus type 1 (BoHV-1) Env gB. In silico analysis revealed a short BoHV-1 gB motif (338YKRD341) within a epitope region, with a high similarity to the motifs shared by the dodecapeptide N-terminal region (5YxARD1) and HSV-1 Env gB (326YARD329), in which the 328Arg residue is described to be a neutralizing antibody target. Besides the characterization of an antibody-binding site of the BoHV-1 Env gB, we have demonstrated that the phage-fused peptide has the potential to be used as a reagent for virus diagnosis by phage-ELISA assay, which discriminated BoHV-1 infected serum samples from negative ones.