PEPTIDE DISPLAY ON FUNCTIONAL TAILSPIKE PROTEIN OF BACTERIOPHAGE-P22

The tailspike protein (TSP) of Salmonella typhimurium P22 bacteriophag e is a multifunctional homotrimer, 6 copies of which are non-covalentl y attached to the capsid to form the virion tail in the last reaction of phage assembly. An antigenic peptide of foot-and-mouth disease viru s (FMDV), aa 134-156 of protein VP1, has been joined to the carboxy te rminus of TSP, and produced as a fusion protein in Escherichia coli di rected by the trp promoter. The resulting fusion protein is soluble, s table, non-toxic, and can be easily purified by standard procedures. M oreover, both the endorhamnosidase and capsid assembly activities of t he TSP are conserved, permitting the fusion protein to reconstitute in fectious viruses by in vitro association with tailless particles. In b oth free TSP and P22 chimeric virions, the foreign peptide is solvent- exposed and highly antigenic, indicating that P22 TSP could be an appr opriate carrier protein for multimeric peptide display.