5ae4

Structures of inactive and activated DntR provide conclusive evidence for the mechanism of action of LysR transcription factors

spinqualitylabelsall models 5ae4, resolution 3.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5ae4 is a 2 chain structure with sequence from Burkholderia cepacia. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.3Å Ligands: SCN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q7WT50_9BURK Publication Abstract from PubMed LysR Type Transcriptional Regulators (LTTRs) regulate basic metabolic pathways or virulence gene expression in prokaryotes. Evidence suggests that the activation of LTTRs involves a conformational change from an inactive compact apo- configuration that represses transcription to an active, expanded holo- form that promotes it. However, no LTTR has yet been observed to adopt both configurations. Here, we report the results of structural studies of various forms of the LTTR DntR. Crystal structures of apo-DntR and of a partially autoinducing mutant H169T-DntR suggest that active and inactive DntR maintain a compact homotetrameric configuration. However, Small Angle X-ray Scattering (SAXS) studies on solutions of apo-, H169T- and inducer-bound holo-DntR indicate a different behaviour, suggesting that while apo-DntR maintains a compact configuration in solution both H169T- and holo-DntR adopt an expanded conformation. Models of the SAXS-obtained solution conformations of apo- and holo-DntR homotetramers in complex with promoter-operator region DNA are consistent with previous observations of a shifting of LTTR DNA binding sites upon activation and a consequent relaxation in the bend of the promoter-operator region DNA. Our results thus provide clear evidence at the molecular level which strongly supports the 'sliding dimer' hypothesis concerning LTTR activation mechanisms. The solution configurations of inactive and activated DntR have implications for the sliding dimer mechanism of LysR transcription factors.,Lerche M, Dian C, Round A, Lonneborg R, Brzezinski P, Leonard GA Sci Rep. 2016 Jan 28;6:19988. doi: 10.1038/srep19988. PMID:26817994 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Transcriptional activator 3D structures

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