Crystal Structure of Spa40 in Shigella flexneri
Author Information
Author(s): Deane Janet E, Graham Stephen C, Mitchell Edward P, Flot David, Johnson Steven, Lea Susan M
Primary Institution: University of Oxford
Hypothesis
The study investigates the role of Spa40 in the type III secretion system of Shigella flexneri and its mechanism of substrate specificity switching.
Conclusion
The cleavage of Spa40 at the NPTH sequence alters its surface properties, which is likely critical for the binding of additional T3SS components.
Supporting Evidence
- Spa40 is cleaved at a conserved NPTH sequence, which is essential for its function.
- The structure of Spa40C reveals a conformational change that is critical for substrate switching.
- Mutations that prevent cleavage of Spa40 result in a loss of function.
- Comparison with homologous proteins from E. coli and Salmonella provides insights into the mechanism of action.
Takeaway
The researchers looked at a protein called Spa40 that helps bacteria inject harmful stuff into our cells, and they found out how it changes shape to do its job better.
Methodology
The study involved protein production, purification, and crystallization, followed by X-ray diffraction analysis to determine the structure of Spa40.
Digital Object Identifier (DOI)
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