FIGURE 3.
Factors that determine the DNA conformation in the ASC. A, global changes in DNA structure. The protein components in the ASC and the FLRC are superimposed. The protein is not displayed, but the DNA that is bound to it is. B and C, close-up views of the target strand in the FLRC and the ASC. The dotted lines indicate the contacts between MutY and the DNA backbone. D, schematic diagram showing the protein-DNA interactions on the target strand in the FLRC and the ASC. E, exo-site contacts on cytosine in the ASC. F, the reversed Watson-Crick base pair observed in ASC. G, structure of a normal Watson-Crick base pair (from the ASC) The blue meshes in panels E and F are σA-weighted 2Fo − Fc map contoured at 1σ. Comparison of oxoG recognition by MutY in ASC and FLRC is shown in panels H–J. H, close-up view of oxoG recognition by MutY in the ASC. Important hydrogen-bonding interactions between oxoG and the protein are denoted by dotted lines. I, close-up view of oxoG recognition by MutY in the FLRC. J, protein superposition of panels A and B. The color coding scheme is the same as Fig. 2 except as specifically noted.