4xxe

Structure of AgrA LytTR domain in complex with promoters

spinqualitylabelsall models 4xxe, resolution 3.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4xxe is a 6 chain structure with sequence from Staphylococcus aureus subsp. aureus COL and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function AGRA_STAAC Required for high-level post-exponential phase expression of a series of secreted proteins. Publication Abstract from PubMed The intracellular trigger for the quorum sensing response mechanism in Staphylococcus aureus involves the phosphorylation of the response regulator AgrA by the membrane anchored histidine kinase AgrC. AgrA activates transcription from three promoter sequences (P1-P3). The promoter strength, conditional association of AgrA with these promoter elements and temporal delay in AgrA-mediated changes in gene expression contribute to the diversity of the quorum sensing response in different S. aureus strains. AgrA promoters comprise of imperfect direct repeats of DNA with a consensus sequence- [TA][AC][CA]GTTN[AG][TG]. Here we describe crystal structures of the DNA-binding (LytTR) domain of AgrA with different cognate DNA sequences that reveal a hitherto unanticipated feature of AgrA-DNA interactions. AgrA promoter interactions are asymmetric with fewer interactions at the binding site proximal to the -35 promoter element. Biochemical assays to evaluate AgrA-promoter interactions suggests that phosphorylation induced dimerization of AgrA can compensate for the asymmetry in AgrA-DNA interactions. The structures also provide a basis to rationalize mutations that were noted to alter AgrA activity without affecting protein-DNA interactions. Put together, the structural data, gene expression and mutational analysis reveal that promoter strength and AgrA phosphorylation enable quorum-sensing triggered transcriptional changes leading to a transition from the persistent to virulent phenotype. Conformational features of the Staphylococcus aureus AgrA-promoter interactions rationalize quorum-sensing triggered gene expression.,Rajasree K, Fasim A, Gopal B Biochem Biophys Rep. 2016 Mar 23;6:124-134. doi: 10.1016/j.bbrep.2016.03.012., eCollection 2016 Jul. PMID:28955870 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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