FIGURE 1.

The crystal structure of T4 Arn and the DNA mimic protein T7 Ocr. A, the Arn dimer and Ocr dimer are shown as schematics. B, the distributions of the negative surface charges on the Arn and Ocr dimers are compared. The carboxyl groups of the acidic amino acids, Glu and Asp, are colored red. C, the negatively charged groups (i.e. C-β carbons on Glu and Asp) of the Arn dimer (gray spheres) and double-stranded B-DNA (orange lines) are compared in the wall-eyed stereo view, and the dsDNA-matched C-β carbons are colored in red spheres.