Figure 5

Anion-π interactions between Asp or Glu and Phe, Tyr or Trp. (a) Energy profile (in kcal/mol) as a function of the interresidue distance d (in Å) in globular proteins (dashed black), extramembrane regions (blue) and transmembrane regions (red). (b) Example of an anion-π interactions in the PDB structure 1A0S (sucrose-specific porin). The negatively charged amino acids are in red, the positively charged ones in blue and the aromatic residues in magenta.