1baz | pdb_00001baz

ARC REPRESSOR MUTANT PHE10VAL

spinqualitylabelsall models 1baz, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1baz is a 4 chain structure with sequence from Salmonella virus P22. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.9Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RARC_BPP22 This protein acts as a transcriptional repressor of its own gene arc and of gene ant. Publication Abstract from PubMed A central question in protein-DNA recognition is the origin of the specificity that permits binding to the correct site in the presence of excess, nonspecific DNA. In the P22 Arc repressor, the Phe-10 side chain is part of the hydrophobic core of the free protein but rotates out to pack against the sugar-phosphate backbone of the DNA in the repressor-operator complex. Characterization of a library of position 10 variants reveals that Phe is the only residue that results in fully active Arc. One class of mutants folds stably but binds operator with reduced affinity; another class is unstable. FV10, one member of the first class, binds operator DNA and nonoperator DNA almost equally well. The affinity differences between FV10 and wild type indicate that each Phe-10 side chain contributes 1.5-2.0 kcal to operator binding but less than 0.5 kcal/mol to nonoperator binding, demonstrating that contacts between Phe-10 and the operator DNA backbone contribute to binding specificity. This appears to be a direct contribution as the crystal structure of the FV10 dimer is similar to wild type and the Phe-10-DNA backbone interactions are the only contacts perturbed in the cocrystal structure of the FV10-operator complex. Origins of DNA-binding specificity: role of protein contacts with the DNA backbone.,Schildbach JF, Karzai AW, Raumann BE, Sauer RT Proc Natl Acad Sci U S A. 1999 Feb 2;96(3):811-7. PMID:9927650 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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