2bjc

NMR structure of a protein-DNA complex of an altered specificity mutant of the lac repressor headpiece that mimics the gal repressor

spinqualitylabelsall models 2bjc Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2bjc is a 4 chain structure with sequence from Escherichia coli. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR, 16 models Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function LACI_ECOLI Repressor of the lactose operon. Binds allolactose as an inducer. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Recognition of the lac operator by the lac repressor involves specific interactions between residues in the repressor's recognition helix and bases in the DNA major groove. Tyr17 and Gln18, at positions 1 and 2 in the lac repressor recognition helix, can be exchanged for other amino acids to generate mutant repressors that display altered specificity. We have solved the solution structure of a protein-DNA complex of an altered-specificity mutant lac headpiece in which Tyr17 and Gln18 were exchanged for valine and alanine, respectively, as found in the recognition helix of the gal repressor. As previously described by Lehming et al. (EMBO J. 1987, 6, 3145-3153), this altered-specificity mutant of the lac repressor recognizes a variant lac operator that is similar to the gal operator Oe. The mutant lac headpiece showed the predicted specificity and is also able to mimic the gal repressor by recognizing and bending the natural gal operator Oe. These structural data show that, while most of the anchoring points that help the lac headpiece to assemble on the lac operator were preserved, a different network of protein-DNA interactions connecting Ala17 and Val18 to bases in the DNA major groove drives the specificity towards the altered operator. Altered specificity in DNA binding by the lac repressor: a mutant lac headpiece that mimics the gal repressor.,Kopke Salinas R, Folkers GE, Bonvin AM, Das D, Boelens R, Kaptein R Chembiochem. 2005 Sep;6(9):1628-37. PMID:16094693 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Lac repressor

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