Biopanning of polypeptides binding to bovine ephemeral fever virus Gprotein from phage display peptide library.

Abstract

BACKGROUND: The bovine ephemeral fever virus (BEFV) glycoprotein neutralization site 1 (also referred as Gprotein), is a critical protein responsible for virus infectivity and eliciting immune-protection, however, binding peptides of BEFV Gprotein are still unclear. Thus, the aim of the present study was to screen specific polypeptides, which bind BEFV Gprotein with high-affinity and inhibit BEFV replication. METHODS: The purified BEFV Gwas coated and then reacted with the M13-based Ph.D.-7 phage random display library. The peptides for target binding were automated sequenced after four rounds of enrichment biopanning. The amino acid sequences of polypeptide displayed on positive clones were deduced and the affinity of positive polypeptides with BEFV Gwas assayed by ELISA. Then the roles of specific G-binding peptides in the context of BEFV infection were analyzed. RESULTS: The results showed that 27 specific peptide ligands displaying 11 different amino acid sequences were obtained, and the T18 and T25 clone had a higher affinity to Gprotein than the other clones. Then their antiviral roles of two phage clones (T25 and T18) showed that both phage polypeptide T25 and T18 exerted inhibition on BEFV replication compared to control group. Moreover, synthetic peptide based on T18 (HSIRYDF) and T25 (YSLRSDY) alone or combined use on BEFV replication showed that the synthetic peptides could effectively inhibit the formation of cytopathic plaque and significantly inhibit BEFV RNA replication in a dose-dependent manner. CONCLUSION: Two antiviral peptide ligands binding to bovine ephemeral fever virus Gprotein from phage display peptide library were identified, which may provide a potential research tool for diagnostic reagents and novel antiviral agents.