3zqf | pdb_00003zqf

Structure of Tetracycline repressor in complex with antiinducer peptide-TAP1

spinqualitylabelsall models 3zqf, resolution 2.56Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3zqf is a 2 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 2.56Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function TETR2_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.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 The allosteric mechanism of one of the best characterized bacterial transcription regulators, tetracycline repressor (TetR), has recently been questioned. Tetracycline binding induces cooperative folding of TetR, as suggested by recent unfolding studies, rather than switching between two defined conformational states, namely a DNA-binding-competent conformation and a non-DNA-binding conformation. Upon ligand binding, a host of near-native multiconformational structures collapse into a single, highly stabilized protein conformation that is no longer able to bind DNA. Here, structure-function studies performed with four synthetic peptides that bind to TetR and mimic the function of low-molecular-weight effectors, such as tetracyclines, provide new means to discriminate between different allosteric models. Whereas two inducing peptides bind in an extended beta-like conformation, two anti-inducing peptides form an alpha-helix in the effector binding site of TetR. This exclusive bimodal interaction mode coincides with two distinct overall conformations of TetR, namely one that is identical with induced TetR and one that mirrors the DNA-bound state of TetR. Urea-induced unfolding studies show no increase in thermodynamic stability for any of the peptide complexes, although fluorescence measurements demonstrate peptide binding to TetR. This strongly suggests that, at least for these peptide effectors, a classical two-state allosteric model best describes TetR function. An Exclusive alpha/beta Code Directs Allostery in TetR-Peptide Complexes.,Sevvana M, Goetz C, Goeke D, Wimmer C, Berens C, Hillen W, Muller YA J Mol Biol. 2011 Dec 9. PMID:22178479 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Tetracycline repressor protein 3D structures

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