Recognition of the N-terminal lectin domain of FimH adhesin by the usher FimD is required for type 1 pilus biogenesis.
In this work we discover that a specific recognition of the N-terminal lectin domain of FimH adhesin by the usher FimD is essential for the biogenesis of type 1 pili in Escherichia coli. These filamentous organelles are assembled by the chaperone-usher pathway, in which binary complexes between fimbrial subunits and the periplasmic chaperone FimC are recognized by the outer membrane protein FimD (the usher). FimH adhesin initiates fimbriae polymerization and is the first subunit incorporated in the filament. Accordingly, FimD shows higher affinity for the FimC/FimH complex although the structural basis of this specificity is unknown. We have analysed the assembly into fimbria, and the interaction with FimD in vivo, of FimH variants in which the N-terminal lectin domain of FimH was deleted or substituted by different immunoglobulin (Ig) domains, or in which these Ig domains were fused to the N-terminus of full-length FimH. From these data, along with the analysis of a FimH mutant with a single amino acid change (G16D) in the N-terminal lectin domain, we conclude that the lectin domain of FimH is recognized by FimD usher as an essential step for type 1 pilus biogenesis.
Munera
Diana
D
Department of Microbial Biotechnology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Campus de Cantoblanco, 28049 Madrid, Spain.
Hultgren
Scott
S
Fernández
Luis Angel
LA
D018830:Adhesins, Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D001224:Aspartic Acid / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000737:chemistry* / Q000378:metabolism*; D010861:Fimbriae, Bacterial / Q000378:metabolism*; D018698:Glutamic Acid / Q000235:genetics; D006801:Humans; D007136:Immunoglobulins / Q000737:chemistry; D037102:Lectins / Q000737:chemistry*; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D017384:Sequence Deletion
D018830:Adhesins, Escherichia coli; D029968:Escherichia coli Proteins; D007136:Immunoglobulins; D037102:Lectins; D050505:Mutant Proteins; D011994:Recombinant Proteins; C489283:fimD protein, E coli; C058769:fimH protein, E coli; D036781:Fimbriae Proteins; D001224:Aspartic Acid; D018698:Glutamic Acid