6qjw

TetR(D) T103A mutant in complex with 7-chlortetracycline and magnesium

spinqualitylabelsall models 6qjw, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6qjw is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.1Å Ligands: CL, CTC, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TETR4_ECOLX TetR is the repressor of the tetracycline resistance element; its N-terminal region forms a helix-turn-helix structure and binds DNA. Binding of tetracycline to TetR reduces the repressor affinity for the tetracycline resistance gene (tetA) promoter operator sites. Publication Abstract from PubMed Allosteric regulation of the Tet repressor (TetR) homodimer relies on tetracycline binding that abolishes the affinity for the DNA operator. Previously, interpretation of circular dichroism data called for unfolding of the alpha-helical DNA-binding domains in absence of binding to DNA or tetracycline. Our small angle X-ray scattering of TetR(D) in solution contradicts this unfolding as a physiological process. Instead, in the core domain crystal structures analyses show increased immobilisation of helix alpha9 and two C-terminal turns of helix alpha8 upon tetracycline binding. Tetracycline complexes of TetR(D) and four single-site alanine variants were characterised by isothermal titration calorimetry, fluorescence titration, X-ray crystal structures, and melting curves. Five crystal structures confirm that Thr103 is a key residue for the allosteric events of induction, with the T103A variant lacking induction by any tetracycline. The T103A variant shows anti-cooperative inducer binding, and a melting curve of the tetracycline complex different to TetR(D) and other variants. For the N82A variant inducer binding is clearly anti-cooperative but triggers the induced conformation. Thermodynamics, cooperativity and stability of the tetracycline repressor (TetR) upon tetracycline binding.,Palm GJ, Buchholz I, Werten S, Girbardt B, Berndt L, Delcea M, Hinrichs W Biochim Biophys Acta Proteins Proteom. 2020 Feb 27;1868(6):140404. doi:, 10.1016/j.bbapap.2020.140404. PMID:32114262 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Tetracycline repressor protein 3D structures

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