Superpositions of ribbon representations of the area around the flap in ligand–BACE1 complexes with open flap conformations crystallizing in different space groups. For comparison, a BACE1 structure with a closed flap is displayed in each representation. (a) Superimposition of all of the BACE1 complexes that crystallized in space group P6122. The cyan and purple structures represent PDB entries 1w51
, respectively. (b) Superimposition of structures belonging to space group C2221: PDB entries 3fkt
(cyan) and our cocrystallized structure (green). (c) Superimposition of structures belonging to space group C121: PDB entries 1ym4
. (d) Superimposition of structures belonging to space group P212121: PDB entries 2vie
. (e) Superimposition of the three copies in the asymmetric unit of PDB entry 3hvg
belonging to space group C2: chain A (green), chain B (cyan) and chain C (magenta). In all cases the inhibitors are displayed as stick models.