Structure of Escherichia coli O157:H7 bacteriophage CBA120 tailspike protein 4 baseplate anchor and tailspike assembly domains (TSP4-N)

Sci Rep. 2022 Feb 8;12(1):2061. doi: 10.1038/s41598-022-06073-2.


Four tailspike proteins (TSP1-4) of Escherichia coli O157:H7 bacteriophage CBA120 enable infection of multiple hosts. They form a branched complex that attaches to the tail baseplate. Each TSP recognizes a different lipopolysaccharide on the membrane of a different bacterial host. The 335 N-terminal residues of TSP4 promote the assembly of the TSP complex and anchor it to the tail baseplate. The crystal structure of TSP4-N335 reveals a trimeric protein comprising four domains. The baseplate anchor domain (AD) contains an intertwined triple-stranded β-helix. The ensuing XD1, XD2 and XD3 β-sheet containing domains mediate the binding of TSP1-3 to TSP4. Each of the XD domains adopts the same fold as the respective XD domains of bacteriophage T4 gp10 baseplate protein, known to engage in protein-protein interactions via its XD2 and XD3 domains. The structural similarity suggests that XD2 and XD3 of TSP4 also function in protein-protein interactions. Analytical ultracentrifugation analyses of TSP4-N335 and of domain deletion proteins showed how TSP4-N335 promotes the formation of the TSP quaternary complex. TSP1 and TSP2 bind directly to TSP4 whereas TSP3 binding requires a pre-formed TSP4-N335:TSP2 complex. A 3-dimensional model of the bacteriophage CBA120 TSP complex has been developed based on the structural and ultracentrifuge information.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Bacteriophages / genetics*
  • Bacteriophages / metabolism*
  • Crystallography, X-Ray
  • Escherichia coli O157 / virology*
  • Genome, Viral / genetics*
  • Glycoside Hydrolases / metabolism*
  • Host Microbial Interactions / physiology
  • Lipopolysaccharides / metabolism
  • Models, Molecular
  • Protein Structure, Quaternary
  • Protein Structure, Tertiary
  • Ultracentrifugation
  • Viral Tail Proteins / metabolism*


  • Lipopolysaccharides
  • Viral Tail Proteins
  • Glycoside Hydrolases
  • tailspike protein, bacteriophage