Globotriaosylceramide (Gb3) is a glycolipid molecule that serves as a receptor for Shiga toxin molecules. Shiga toxin molecules are produced by some strains of E. coli bacteria. Infection with Shiga toxin-producing bacteria can lead to hemorrhagic colitis in adults and hemolytic uremic syndrome in children. Shiga toxin B subunits each contain three possible sites for binding Gb3 molecules. Software from the NCBI site was utilized in order to conduct searches for proteins with binding sites similar to that of a Shiga toxin site 3 binding site. By identifying protein chains in the databases containing protein data bank (pdb) files that contain amino acid sequences similar to those of Shiga toxin site 3 binding sites, we were able to find new potential Gb3 binding sites on non-Shiga toxin proteins. Cn3d software was used to evaluate the structure of these potential binding sites on proteins and determine whether or not they may serve as likely Gb3 binding sites. Potential binding sites so identified were rated using letters A-D to determine how similar the cleft was to that of an actual Shiga toxin site 3 Gb3 binding site.
