Structural and functional insight into the carbohydrate receptor binding of F4 fimbriae-producing enterotoxigenic Escherichia coli

Abstract

Background: F4 fimbriae produced by enterotoxigenic Escherichia coli mediate attachment to eukaryotic host receptors. Results: The structure of lactose bound to the F4 fimbrial adhesin FaeGad was elucidated. Conclusion: Lactose interacts at a subdomain grafted on the FaeGad core domain. Significance: The co-complex structure explains the finely tuned receptor specificity of F4ad fimbriae; additionally, the carbohydrate binding site differs among FaeG variants.