As seen in Fig 8, SB-206553 exhibits a binding mode in the α7 nAChR-ECD where the amino group of the carbamate establishes a hydrogen bond with the carbonyl group of Asp133, whereas the pyrroloindole moiety appears located between Phe151 and Phe155, a position that would favor π-stacking interactions between the corresponding aromatic rings.
Source: wiktionary