Crystal Structure of the Cell-Binding B Oligomer of Verotoxin-1 from E. Coli.Stein, P.E., Boodhoo, A., Tyrrell, G.J., Brunton, J.L., Read, R.J.
(1992) Nature 355: 748
- PubMed: 1741063
- DOI: https://doi.org/10.1038/355748a0
- Primary Citation of Related Structures:
- PubMed Abstract:
The Shiga toxin family, a group of cytotoxins associated with diarrhoeal diseases and the haemolytic uraemic syndrome, includes Shiga toxin from Shigella dysenteriae type 1 and verotoxins produced by enteropathogenic Escherichia coli. The family belongs to the A-B class of bacterial toxins, which includes the cholera toxin family, pertussis and diphtheria toxins. These toxins all have bipartite structures consisting of an enzymatic A subunit associated with a B oligomer which binds to specific cell-surface receptors, but their amino-acid sequences and pathogenic mechanisms differ. We have determined the crystal structure of the B oligomer of verotoxin-1 from E. coli. The structure unexpectedly resembles that of the B oligomer of the cholera toxin-like heat-labile enterotoxin from E. coli, despite the absence of detectable sequence similarity between these two proteins. This result implies a distant evolutionary relationship between the Shiga toxin and cholera toxin families. We suggest that the cell surface receptor-binding site lies in a cleft between adjacent subunits of the B pentamer, providing a potential target for drugs and vaccines to prevent toxin binding and effect.
Department of Medical Microbiology and Infectious Diseases, University of Alberta, Edmonton, Canada.