Solution structure of the complex between the B-subunit homopentamer of verotoxin VT-1 from Escherichia coli and the trisaccharide moiety of globotriaosylceramide.

We report the solution structure of the carbohydrate-binding B subunit of verotoxin VT-1 (VTB) from enterohemorrhagic Escherichia coli in association with the trisaccharide Galalpha1-4Galbeta1-4Glcbeta1-O-trimethylsilylethyl , determined by use of stable isotope-assisted NMR techniques. In contrast to the crystal structure of the complex which predicts three binding sites per monomer, only one of these sites is observed with substantial occupancy by the trisaccharide in solution.