Fig. (5) Example of differently oriented side chain in a case where two Cα atoms are well superposed. Most of these cases refer to residues that are very exposed to the solvent. Only very few cases refer to residues that are buried in the protein interior. This is the case of Tyr 48 in (a) 1W8L (X-ray structure) and (b) model 1 of 1OCA (NMR structure). Figure is prepared using PyMOL [64].