Figure 2.

Omit electron density maps calculated using |F_o| – |F_c| coefficients for aniracetam and CX614. A, Electron density for aniracetam contoured at 2.5σ. B, Electron density for CX614, also contoured at 2.5σ. For each modulator, the fit of the molecular structure to the electron density is shown for each of the twofold related positions of the modulator; on the top rows, the views are perpendicular to molecular twofold axis, whereas in the bottom rows, the views are parallel to the molecular twofold axis.