Figure 2.

Stereoview of the GAAA duplex illustrating the twofold symmetry of the double helix and the curvature of the axis. A crystallographically related helix stacks coaxially as described in the text. Repetition of this interaction generates pseudoinfinite helices throughout the crystal. The local helix axes are shown as thick lines through the helix. The bound Mn²⁺ ions are shown as spheres. Bound waters are not shown in this illustration.