5yek

Crystal structure of BioQ

spinqualitylabelsall models 5yek, resolution 2.19Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5yek is a 2 chain structure with sequence from Mycolicibacterium smegmatis MC2 155. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.191Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0QX69_MYCS2 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.[ARBA:ARBA00002856] Publication Abstract from PubMed BACKGROUND: Biotin is an essential cofactor in living organisms. The TetR family transcriptional regulator (TFTR) BioQ is the main regulator of biotin synthesis in Mycobacterium smegmatis. BioQ represses the expression of its target genes by binding to a conserved palindromic DNA sequence (the BioQ operator). However, the mechanism by which BioQ recognizes this DNA element has not yet been fully elucidated. METHODS/RESULTS: We solved the crystal structures of the BioQ homodimer in its apo-form and in complex with its specific operator at 2.26A and 2.69A resolution, respectively. BioQ inserts the N-terminal recognition helix of each protomer into the corresponding major grooves of its operator and stabilizes the formation of the complex via electrostatic interactions and hydrogen bonding to induce conformational changes in both the DNA and BioQ. The DNA interface of BioQ is rich in positively charged residues, which help BioQ stabilize DNA binding. We elucidated the structural basis of DNA recognition by BioQ for the first time and identified the amino acid residues responsible for DNA binding via further site-directed mutagenesis. GENERAL SIGNIFICANCE: Our findings clearly elucidate the mechanism by which BioQ recognizes its operator in the biotin synthesis pathway and reveal the unique structural characteristics of BioQ that are distinct from other TFTR members. Structural insights into operator recognition by BioQ in the Mycobacterium smegmatis biotin synthesis pathway.,Yan L, Tang Q, Guan Z, Pei K, Zou T, He J Biochim Biophys Acta Gen Subj. 2018 Sep;1862(9):1843-1851. doi:, 10.1016/j.bbagen.2018.05.015. Epub 2018 May 28. PMID:29852200 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Tetracycline repressor protein 3D structures

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