The amino-terminal domain of the P-pilus adhesin determines receptor specificity.
Pyelonephritic isolates of Escherichia coli commonly express P-pili, which mediate bacterial attachment to glycolipids on epithelial cell surfaces. Three classes of P-pili have been defined, based on varying specificity for galabiose-containing glycolipids. Variation in adhesive capacity is correlated with a shift in preferred host, suggesting that host tropism depends largely on detailed specificity for the globoseries glycolipids. In this study we examined the importance of the PapG adhesin in determining receptor specificity. Translational fusions were constructed between the amino-terminus of the PapG adhesin from each of the three pilus classes and a reporter protein. The binding specificity of the purified fusion proteins in vitro was identical to that seen with whole bacteria. Adherence of intact bacteria to cultured kidney cells was markedly reduced by a monoclonal antibody specific for the Class III adhesin (previously denoted PrsG), confirming the importance of the amino-terminus of PapG in mediating attachment to a receptor when presented on the eukaryotic cell surface. These results suggest that the detailed receptor specificity resides solely within the amino-terminus of the PapG adhesin and is independent of the complex pilus architecture.
Haslam
D B
DB
Department of Molecular Microbiology, Washington University School of Medicine St. Louis, Missouri 63110.
Borén
T
T
Falk
P
P
Ilver
D
D
Chou
A
A
Xu
Z
Z
Normark
S
S
D018830:Adhesins, Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D002240:Carbohydrate Sequence; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D036781:Fimbriae Proteins; D006017:Glycolipids / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D011704:Pyelonephritis / Q000382:microbiology; D011971:Receptors, Immunologic / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D018830:Adhesins, Escherichia coli; D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; D017931:DNA Primers; D004269:DNA, Bacterial; D006017:Glycolipids; C092426:PapG protein, E coli; D011971:Receptors, Immunologic; D011993:Recombinant Fusion Proteins; C037872:pili, bacterial receptor; D036781:Fimbriae Proteins