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spinqualitylabelsall models 3D Representation of CzrA with Zn Bound Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

DNA Bound StateDNA Bound State

The have been found to occur at the Ser 54 and 57 along with His 58. These residues are likely to interact with the 5'-TGAA sequence found in the half-site of the DNA. These residues are found in the N terminal of the R helix. The residues involved in the are Val 42 and Gln 53. This was experimentally determined by replacing the Gln and Val with Ala residues and measuring the binding capacity; In a previously published article, the DNA bound state of CzrA was tested by using the known critical residues for DNA interactions. Critical residues, Gln53, Val42, Ser54, Ser57, and His58, were replaced with Ala and then compared to the kinetics of the wild type protein. Replacing only the Q53 and V42 residues resulted in an 11-fold and 160-fold decrease in K_a, respectively. Other residues such as S54, S57, and H58 were also replaced with Ala residues, and it was found that these mutations caused binding similar to the fully inhibited Zn²⁺ bound state. Table 1 in this articel show the different K_observed, and the measured decrease in K_observed for each mutation.

Zinc Ligand(s)Zinc Ligand(s)

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ReferencesReferences

Arunkumar A., Campanello G., Giedroc D. (2009). Solution Structure of a paradigm ArsR family zinc sensor in the DNA-bound state. PNAS 106:43 18177-18182

Penella M., Shokes J., Cosper N., Scott R.,Giedroc D. (2002). Structural elements of metal selectivity in metal sensor proteins. PNAS 100:7 3713-3718.