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Self-associating autotransporters, SAATs: functional and structural similarities
Per Klemm1, Rebecca Munk Vejborg, Orla Sherlock
1Microbial Adhesion Group, Center of Biomedical Microbiology, Building 301, BioCentrum-DTU, Technical University of Denmark, DK-2800 Lyngby, Denmark. pkl@biocentrum.dtu.dk
International Journal of Medical Microbiology : IJMM
|April 8, 2006
Summary
Gram-negative bacteria possess self-associating autotransporter proteins that promote bacterial aggregation and biofilm formation. These proteins, including TibA, AIDA, and Ag43, are key virulence factors in Escherichia coli.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Pathogenesis
Background:
- Autotransporter proteins are common in Gram-negative bacteria, featuring signal, passenger, and translocator domains.
- This protein family includes significant virulence factors and plays a role in bacterial interactions.
- Specific examples in Escherichia coli include TibA, AIDA, and Ag43, which share functional similarities despite sequence differences.
Purpose of the Study:
- To investigate the common properties and propose a classification for a subgroup of autotransporter proteins.
- To highlight the roles of TibA, AIDA, and Ag43 in bacterial aggregation and biofilm formation.
Main Methods:
- Sequence analysis to determine protein identity.
- Functional characterization of protein-protein interactions and aggregation.
- Assessment of biofilm formation enhancement.
Main Results:
- TibA, AIDA, and Ag43 share approximately 25% sequence identity and exhibit self-associating properties.
- These proteins induce bacterial aggregation and can form mixed aggregates through heterologous interactions.
- The proteins were found to enhance biofilm formation in Escherichia coli.
Conclusions:
- A new classification, self-associating autotransporters (SAATs), is proposed for proteins like TibA, AIDA, and Ag43.
- SAATs are crucial for bacterial adhesion, aggregation, and biofilm development, contributing to virulence.
- Understanding SAATs provides insights into bacterial community dynamics and pathogenesis.
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