1lkt
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CRYSTAL STRUCTURE OF THE HEAD-BINDING DOMAIN OF PHAGE P22 TAILSPIKE PROTEIN
OverviewOverview
The tailspike protein of Salmonella phage P22 is a viral adhesion protein, with both receptor binding and destroying activities. It recognises the, O-antigenic repeating units of cell surface lipopolysaccharide of, serogroup A, B and D1 as receptor, but also inactivates its receptor by, endoglycosidase (endorhamnosidase) activity. In the final step of, bacteriophage P22 assembly six homotrimeric tailspike molecules are, non-covalently attached to the DNA injection apparatus, mediated by their, N-terminal, head-binding domains. We report the crystal structure of the, head-binding domain of P22 tailspike protein at 2.3 A resolution, solved, with a recombinant telluromethionine derivative and non-crystallographic, symmetry averaging. The trimeric dome-like structure is formed by two, perpendicular beta-sheets of five and three strands, respectively in each, subunit and caps a three-helix bundle observed in the structure of the, C-terminal receptor binding and cleaving fragment, reported here after, full refinement at 1.56 A resolution. In the central part of the receptor, binding fragment, three parallel beta-helices of 13 complete turns are, associated side-by-side, while the three polypeptide strands merge into a, single domain towards their C termini, with close interdigitation at the, junction to the beta-helix part. Complex structures with receptor, fragments from S. typhimurium, S. enteritidis and S. typhi253Ty determined, at 1.8 A resolution are described in detail. Insertions into the, beta-helix form the O-antigen binding groove, which also harbours the, active site residues Asp392, Asp395 and Glu359. In the intact structure of, the tailspike protein, head-binding and receptor-binding parts are, probably linked by a flexible hinge whose function may be either to deal, with shearing forces on the exposed, 150 A long tailspikes or to allow, them to bend during the infection process.
About this StructureAbout this Structure
1LKT is a Single protein structure of sequence from Yersinia phage py54. Full crystallographic information is available from OCA.
ReferenceReference
Phage P22 tailspike protein: crystal structure of the head-binding domain at 2.3 A, fully refined structure of the endorhamnosidase at 1.56 A resolution, and the molecular basis of O-antigen recognition and cleavage., Steinbacher S, Miller S, Baxa U, Budisa N, Weintraub A, Seckler R, Huber R, J Mol Biol. 1997 Apr 11;267(4):865-80. PMID:9135118
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