Misplaced but correct ligand. In the structure of Streptomyces coelicolor cytochrome P450 158A2, PDB entry 1se6
(Zhao et al., 2005), the MES A632 molecule is correctly identified but is placed in the electron density in an incorrect pose (a), as clearly confirmed by manual rebuilding and real-space refinement in Coot after rotating the buffer molecule by 180° (b). The 1.75 Å resolution mFo − DFc maps contoured at ±3σ (green/red) and 2mFo − DFc maximum-likelihood omit maps contoured at 1σ (blue) are shown. Maps were calculated for a refined model with the ligand atoms omitted.