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Function and molecular architecture of the Yersinia injectisome tip complex
Petr Broz1, Catherine A Mueller, Shirley A Müller
1Biozentrum der Universität Basel, Basel, Switzerland.
Molecular Microbiology
|August 19, 2007
Summary
The Yersinia enterocolitica injectisome needle comprises 139 YscF subunits. Its tip complex, formed by LcrV monomers, is crucial for YopB insertion into host cell membranes, enabling bacterial pathogenesis.
Area of Science:
- Microbiology
- Molecular Biology
- Structural Biology
Background:
- The Yersinia enterocolitica injectisome is a key virulence factor.
- Understanding the structure and function of the injectisome's tip complex is vital for deciphering bacterial infection mechanisms.
Purpose of the Study:
- To determine the subunit composition and structural organization of the Yersinia enterocolitica injectisome needle and tip complex.
- To investigate the role of the LcrV tip complex in the translocation of effector proteins, specifically YopB, into host cells.
Main Methods:
- Quantitative immunoblot analyses to determine protein subunit stoichiometry.
- Scanning transmission electron microscopy (STEM) for high-resolution structural imaging.
- Construction and functional testing of LcrV-PcrV and LcrV-AcrV hybrids.
- Haemolysis assays to assess translocation pore formation.
Main Results:
- The injectisome needle is composed of approximately 139 YscF subunits.
- The tip complex is formed by three to five LcrV monomers, with a pentameric model providing the best fit.
- The N-terminal globular domain of LcrV is essential for YopB insertion into erythrocyte membranes.
- Functional correlation observed between haemolysis, YopB membrane insertion, and interaction with the LcrV N-terminal domain.
Conclusions:
- The base of the LcrV tip complex is critical for the functional insertion of YopB into host cell membranes.
- Structural insights into the injectisome tip complex provide a foundation for understanding Yersinia pathogenesis and developing targeted interventions.
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