(A) Crystal structure of the SNX5 PX domain (yellow) in complex with IncE residues 107–132 (magenta) shown in cartoon representation. (B) Backbone atoms of the SNX5 and IncE proteins are shown to highlight the prominent β-sheet augmentation mediating the association between the two molecules. (C) Close up view of the SNX5-IncE interface highlighting specific contact areas at the N-terminus of the IncE peptide. (D) Close up of the SNX5-IncE interface highlighting specific contact areas at the hairpin loop of the IncE peptide shown at 90° to Figure 4C. (E). Close up of the SNX5-IncE interface highlighting contact areas at the C-terminus of the IncE peptide in approximately the same orientation as Figure 4C. Residues in SNX5 (Phe136) and IncE (Phe116) that are critical for binding based on mutagenesis are boxed.