The two binding sites on the His-15 residue of HEWL. Fo − Fc density OMIT maps (green) and anomalous difference density (orange) maps at the 3σ cut-off level for (a) and (b) 4dd7
processed by XDS and EVAL, (c) and (d) 4dd9
processed by XDS and EVAL and (e) and (f) 4g4c
processed by XDS and EVAL, respectively. The Nδ binding site is on the left-hand side and the N∊ binding site is on the right-hand side. The arrows show where the possible Cl atom locations are based on anomalous difference density being seen.