title: Molecular structure of adhesin domains in Escherichia coli fimbriae.
abstract: Crystal structures of FimH, PapG, GafD, and DraE fimbrial adhesin subunits or lectin domains have been resolved. These adhesins bind to different targets and are only distantly related in amino acid sequence. The overall structures of the fimbrial lectins, however, appear similar, suggesting that the fimbrial lectins have diverged from a common scaffold. FimH, PapG and GafD are two-domain structures connected by a flexible linker, and the N-terminal adhesin domains have an elongated beta-barrel jelly roll fold that contains the receptor-binding groove. The adhesin domains differ in disulfide patterns, in size and location of the ligand-binding groove, as well as in mechanism of receptor binding. Minor sequence variations that can be either distant from, near to, or at the ligand-binding groove have profound effects on receptor binding by the fimbriae; this is particularly apparent with FimH. The existing structures give insight into the molecular basis of the diversity in fimbrial lectins.
authors.affiliation: General Microbiology, Department of Biological and Environmental Sciences, Faculty of Biosciences, FIN-00014 University of Helsinki, Finland. benita.westerlund@helsinki.fi
authors.forename: Benita
authors.initials: B
authors.lastname: Westerlund-Wikström
authors.forename: Timo K
authors.initials: TK
authors.lastname: Korhonen
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry* / Q000378:metabolism; D018830:Adhesins, Escherichia coli / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001422:Bacterial Adhesion / Q000502:physiology*; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000737:chemistry; D006801:Humans; D037181:Lectins, C-Type / Q000737:chemistry / Q000378:metabolism; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation; D011956:Receptors, Cell Surface / Q000378:metabolism
chemical_list: D018829:Adhesins, Bacterial; D018830:Adhesins, Escherichia coli; D037181:Lectins, C-Type; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D011956:Receptors, Cell Surface; C058769:fimH protein, E coli; D036781:Fimbriae Proteins