Figure 1.
2mFo-DFc (blue, contoured at 1.5σ) and mFo-DFc (green/red, 3.0σ/–3.0σ) electron densities for the original (a and c) and re-refined (b and d) structures for two representative regions, shown in wall-eye stereo views. The original and re-refined models are shown in yellow and cyan sticks, respectively. The red cross-hairs in a represent water molecules. Strong positive difference density corresponding to the missing nucleotide (a) or phosphodiester bond (c) is indicated by the green arrows.