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Chapter 3 : AraC Family Regulators and Transcriptional Control of Bacterial Virulence Determinants
This chapter focuses on selected members of the AraC/XylS family of regulatory proteins as a potential model system to study the induction of genes related to bacterial virulence in human infections. The structural analysis of an AraC family member, Rob, demonstrated some similarities to MarA but also some significant differences, suggesting that alternative modes of DNA binding may influence transcriptional activation relative to different promoter contexts. The activation of the AraC family regulators by their cognate ligand becomes an interesting variable when considering the number of AraC family proteins likely to be involved in the induction of virulence-related genes. The modulation of DNA binding by small molecules specific for AraC family members is a key issue when considering whether disruption of the activation process could be a useful therapeutic strategy. Arabinose binding frees the arms from their interaction with the DNA-binding domain, allowing a preferential interaction with the dimerization domain. Infections with bacteria producing urease often result in cystitis and acute pyelonephritis and can progress to bacteremia. Structural analysis of the AraC proteins has been slowed because of the general aggregation properties of these proteins, but new information is accumulating through the recognition of different functional domains, the construction of chimeric proteins, and the use of genetic approaches. The AraC family includes many transcriptional activators that enhance the production of bacterial virulence determinants.
Key Concept Ranking
- Type III Secretion System