Screening And Characterization Of TGEV M Protein-derived Peptides

Porcine transmissible gastroenteritis virus is one of the important pathogens that causediarrhea in pigs, exist widely in the world, caused huge losses to the pig industry. M protein is themajor structural protein of the TGEV particles, play an important role in induce interferon and theassembly of the virus particle. M gene sequences is conservative, As TGEV molecular biologydiagnostic candidate genes, M genes provide a theoretical basis.In our study,positive plasmid PGEX-TGEV-M was expressed in E. coli expression system. MThe purified protein as a target protein, then used phage display random peptide library to panningit for5rounds, screened out tagged protein in the second round, screend10phage clones, wherein3phage clones has the relative highest binding specificity with the M protein, named phTGEV-M5;phTGEV-M6; phTGEV-M7respectively. Further research on it, include established differentialdiagnosis experiment for identification TGEV from other swine diseases. We also proved that thephage-ELISA was more sensitive than conventional antibody-ELISA (p<0.01), but not as good asRT-PCR.Synthetic peptide which has the highest binding active with the virus (HALTPIKYIPPG),named pepTGEV-M7. Evaluation its ability of inhibition virus. We proved the peptide couldspecific binding with M protein. Plaque reduction experiments revealed pepTGEV-M7mixed withthe the virus previously and then incubated ST cells could notable reduce the TGEV infections invitro (p<0.01). Compared with combined peptides (Mixing pepTGEV-M7with porcineaminopeptidase N polypeptide pepF (FKPSSPPSITLW)) and pepTGEV-M7alone, the former has abetter effect, and peptides inhibited virus in a does-dependent manner.