Download MendeleyStructure of the shiga-like toxin I B-pentamer complexed with an analogue of its receptor Gb3.
Ling, H., Boodhoo, A., Hazes, B., Cummings, M.D., Armstrong, G.D., Brunton, J.L., Read, R.J.(1998) Biochemistry 37: 1777-1788
- PubMed: 9485303
- DOI: https://doi.org/10.1021/bi971806n
- Primary Citation of Related Structures:
1BOS - PubMed Abstract:
Shiga-like toxin I (SLT-I) is a virulence factor of Escherichia coli strains that cause disease in humans. Like other members of the Shiga toxin family, it consists of an enzymatic (A) subunit and five copies of a binding subunit (the B-pentamer). The B-pentamer binds to a specific glycolipid, globotriaosylceramide (Gb3), on the surface of target cells and thereby plays a crucial role in the entry of the toxin. Here we present the crystal structure at 2.8 A resolution of the SLT-I B-pentamer complexed with an analogue of the Gb3 trisaccharide. The structure reveals a surprising density of binding sites, with three trisaccharide molecules bound to each B-subunit monomer of 69 residues. All 15 trisaccharides bind to one side of the B-pentamer, providing further evidence that this side faces the cell membrane. The structural model is consistent with data from site-directed mutagenesis and binding of carbohydrate analogues, and allows the rational design of therapeutic Gb3 analogues that block the attachment of toxin to cells.
Organizational Affiliation:
Department of Biochemistry, University of Alberta, Edmonton, Canada.
