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Pilus chaperone FimC-adhesin FimH interactions mapped by TROSY-NMR
M Pellecchia1, P Sebbel, U Hermanns
1Institut für Molekularbiologie und Biophysik, Eidgenössische Technische Hochschule Hönggerberg, Zürich, Switzerland.
Nature Structural Biology
|April 14, 1999
Summary
Researchers identified how the FimC chaperone binds to the FimH pilus subunit in Escherichia coli. This interaction is crucial for type-1 pilus assembly and bacterial adhesion, revealing FimC binds a folded FimH form.
Area of Science:
- Bacteriology
- Structural Biology
- Molecular Mechanisms
Background:
- Type-1 pili are essential filamentous protein complexes on pathogenic Escherichia coli.
- These pili, anchored to the bacterial outer membrane, mediate host cell adhesion.
- The periplasmic chaperone FimC is vital for type-1 pilus assembly.
Purpose of the Study:
- To identify the specific binding sites on FimC for the FimH pilus subunit.
- To elucidate the structural basis of FimC-FimH interaction using NMR.
- To understand how FimC facilitates type-1 pilus assembly.
Main Methods:
- Nuclear Magnetic Resonance (NMR) spectroscopy, including 15N and 1H chemical shift mapping.
- Transverse relaxation-optimized spectroscopy (TROSY) was employed.
- Structural analysis of the FimC-FimH interaction interface.
Main Results:
- The FimH-binding surface on FimC was precisely mapped using NMR chemical shift perturbation.
- This binding surface is predominantly located on the N-terminal domain of FimC.
- The characteristics of the binding interface suggest FimC interacts with a folded conformation of FimH.
Conclusions:
- The N-terminal domain of FimC is the primary interaction site for FimH.
- FimC likely binds to a pre-folded FimH subunit during type-1 pilus assembly.
- This finding provides critical insights into the molecular machinery of type-1 pilus biogenesis in E. coli.