3f6j
F17a-G lectin domain with bound GlcNAc(beta1-3)Gal
Structural highlights
FunctionF17AG_ECOLX Essential fimbrial adhesion factor that mediates binding to N-acetylglucosamine-containing receptors in the host intestinal microvilli, leading to colonization of the intestinal tissue, and diarrhea or septicemia. Also confers adhesiveness to laminin and basement membranes. Publication Abstract from PubMedFimbriae are long, proteinaceous adhesion organelles expressed on the bacterial envelope, evolutionarily adapted by Escherichia coli strains for the colonization of epithelial linings. Using glycan arrays of the Consortium for Functional Glycomics (CFG), the lectin domains were screened of the fimbrial adhesins F17G and FedF from enterotoxigenic E. coli (ETEC) and of the FimH adhesin from uropathogenic E. coli. This has led to the discovery of a more specific receptor for F17G, GlcNAcb1,3Gal. No significant differences emerged from the glycan binding profiles of the F17G lectin domains from five different E. coli strains. However, strain-dependent amino acid variations, predominantly towards the positively charged arginine, were indicated by sulfate binding in FedF and F17G crystal structures. For FedF, no significant binders could be observed on the CFG glycan array. Hence, a shotgun array was generated from microvilli scrapings of the distal jejunum of a 3-week old piglet about to be weaned. On this array, the blood group A type 1 hexasaccharide emerged as a receptor for the FedF lectin domain and remarkably also for F18-fimbriated E. coli. F17G was found to selectively recognize glycan species with a terminal GlcNAc, typifying intestinal mucins. In conclusion, F17G and FedF recognize long glycan sequences that could only be identified using the shotgun approach. Interestingly, ETEC strains display a large capacity to adapt their fimbrial adhesins to ecological niches via charge-driven interactions, congruent with binding to thick mucosal surfaces displaying an acidic gradient along the intestinal tract. Structural Sampling of Glycan Interaction Profiles Reveals Mucosal Receptors for Fimbrial Adhesins of Enterotoxigenic Escherichia coli.,Lonardi E, Moonens K, Buts L, de Boer AR, Olsson JD, Weiss MS, Fabre E, Guerardel Y, Deelder AM, Oscarson S, Wuhrer M, Bouckaert J Biology (Basel). 2013 Jul 1;2(3):894-917. doi: 10.3390/biology2030894. PMID:24833052[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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