The Structural Basis of Receptor-Binding by Escherichia Coli Associated with Diarrhea and Septicemia
Merckel, M.C., Tanskanen, J., Edelman, S., Westerlund-Wikstrom, B., Korhonen, T.K., Goldman, A.(2003) J Mol Biol 331: 897
- PubMed: 12909017 
- DOI: https://doi.org/10.1016/s0022-2836(03)00841-6
- Primary Citation of Related Structures:  
1OIO - PubMed Abstract: 
GafD in Escherichia coli G (F17) fimbriae is associated with diarrheal disease, and the structure of the ligand-binding domain, GafD1-178, has been determined at 1.7A resolution in the presence of the receptor sugar N-acetyl-D-glucosamine. The overall fold is a beta-barrel jelly-roll fold. The ligand-binding site was identified and localized to the side of the molecule. Receptor binding is mediated by side-chain as well main-chain interactions. Ala43-Asn44, Ser116-Thr117 form the sugar acetamide specificity pocket, while Asp88 confers tight binding and Trp109 appears to position the ligand. There is a disulfide bond that rigidifies the acetamide specificity pocket. The three fimbrial lectins, GafD, FimH and PapG share similar beta-barrel folds but display different ligand-binding regions and disulfide-bond patterns. We suggest an evolutionary path for the evolution of the very diverse fimbrial lectins from a common ancestral fold.
Organizational Affiliation: 
Structural Biology and Biophysics, Institute of Biotechnology, Viikki Biocenter, University of Helsinki, PO Box 56, FIN-00014 Helsinki, Finland.