Function
Tailspike protein (TSP) of bacteriophage P22 is a trimeric protein which serves as the receptor-binding protein of the bacteriophage to its bacterial host[1]. O-antigen polysaccharides found on the outer surface of bacteria are the natural substrates for TSP[2].
Relevance
Bacteriophage research is becoming important due to antibiotics resistance. TSP binding to pathogenic bacteria can be used for their detection[3].
Structural highlights
The C-terminal domain (CTD) (residues 109-end) of TSP is responsible for the attachment of the tailspike protein to the O-antigen moiety on bacterial cell surface. The 3D structure of an octasaccharide bound to CTP of TSP shows numerous hydrophobic interactions as well as well defined water molecules forming hydrogen bonds to the antigen[4].
