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Publication Abstract from PubMed

The Staphylococcus aureus agr quorum sensing system plays a major role in the transition from the persistent to the virulent phenotype. S. aureus agr type (I-IV) strains are characterized by mutations in the sensor domain of the histidine kinase AgrC and differences in the sequence of the secreted auto-inducing peptides (AIP). Here we demonstrate that interactions between the cytosolic domain of AgrC (AgrCCyto) and the response regulator domain of AgrA (AgrARR) dictate the spontaneity of the cellular response to AIP stimuli. The crystal structure of AgrCCyto provided a basis for a mechanistic model to understand AgrC-AgrA interactions. This model enabled an analysis of the biochemical and biophysical parameters of AgrC-AgrA interactions in the context of the conformational features of the AgrC-AgrA complex. This analysis revealed distinct sequence and conformational features that determine the affinity, specificity and kinetics of the phosphotransfer reaction. This step, that governs the response time for transcriptional re-engineering triggered by an AIP stimulus, is independent of the agr type and similar for agonist or antagonist stimuli. These experimental data could serve as a basis to validate simulations of the quorum sensing response and for strategies that employ the agr quorum sensing system to combat biofilm formation in S. aureus infection.

Influence of the AgrC-AgrA complex in the response time of Staphylococcus aureus quorum sensing.,Srivastava SK, Rajasree K, Fasim A, Arakere G, Gopal B J Bacteriol. 2014 May 23. pii: JB.01530-14. PMID:24858185^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.