The tailspike protein (P22TSP) of Enterobacteria phage P22 mediates the recognition and adhesion between the bacteriophage and the surface of Salmonella enterica cells.

It is anchored within the viral coat and recognizes the O-antigen portion of the lipopolysaccharide (LPS) on the outer-membrane of Gram-negative bacteria.

[3] Some mutations affect the folding efficiency of the protein but have no effect on the final native structure.

[6] These carbohydrates share the same main chain trisaccharide repeating unit alpha-D-mannose-(1—4)-alpha-L-rhamnose-(1—3)-alpha-D-galactose-(1—2), but each have a different 2,6-dideoxyhexose substituent at C-3 of the mannose.

P22TSP has endorhamnosidase activity and cleaves the glycosidic bond of the rhamnose group, producing an octasaccharide product.

The secondary structure of P22TSP is dominated by a parallel Beta helix comprising 13 complete turns.

Both of these tailspike proteins also contain right-handed parallel beta-helices and share similar O-antigen binding and cleavage to P22TSP.

[14] Tailspike proteins have also shown potential for more translational applications such as fighting bacterial infections.

A study has demonstrated that orally administered P22TSP markedly reduced Salmonella colonization in a group of chickens.