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Location of binding sites on common type 1 fimbriae from Escherichia coli

G Sweeney, J H Freer

    Journal of General Microbiology
    |June 1, 1979
    PubMed

    Insights

    Ultrasound treatment shortened common type 1 fimbriae from Escherichia coli, reducing their hemagglutinating capacity. Binding ability to erythrocytes decreased less, suggesting a lateral binding site for hemagglutination.

    Area of Science:

    • Microbiology
    • Molecular Biology
    • Biophysics

    Background:

    • Escherichia coli commonly possess type 1 fimbriae, which are proteinaceous appendages involved in bacterial adhesion.
    • Fimbriae mediate hemagglutination, a process crucial for bacterial interaction with host cells.
    • Understanding the structural basis of fimbrial function is essential for developing targeted antimicrobial strategies.

    Purpose of the Study:

    • To investigate the relationship between the length of type 1 fimbriae and their hemagglutinating activity.
    • To elucidate the binding mechanism of type 1 fimbriae to erythrocytes.
    • To determine the location of the binding site responsible for hemagglutination.

    Main Methods:

    • Isolation of common type 1 fimbriae from Escherichia coli.
    • Ultrasound treatment to alter fimbrial length.
    • Assessment of hemagglutinating capacity.
    • Binding assays using erythrocytes and liposomes.
    • Analysis of fimbrial binding to inside-out vesicles from horse erythrocytes.

    Main Results:

    • Ultrasound treatment resulted in a decrease in the length of type 1 fimbriae.
    • Shortened fimbriae exhibited reduced hemagglutinating capacity.
    • The ability of fimbriae to bind to erythrocytes decreased proportionally less than their hemagglutinating capacity.
    • Isolated fimbriae did not agglutinate inside-out vesicles or liposomes, indicating non-hydrophobic binding.

    Conclusions:

    • Fimbrial length is a critical factor influencing hemagglutination.
    • The binding mechanism of type 1 fimbriae is not solely dependent on hydrophobic interactions.
    • Results suggest a lateral location for the fimbrial binding site mediating hemagglutination, rather than a terminal one.

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