Decisive Influence of Environment on Aromatic/Aromatic Interaction Geometries. Comparison of Aromatic/Aromatic Interactions in Crystal Structures of Small Molecules and in Protein Structures

Geometries of aromatic/aromatic interactions in crystal structures small molecules from the Cambridge Structural Database (CSD) (benzene/benzene, toluene/toluene, and p-phenol/p-phenol interactions) protein Protein Data Bank (PDB) (Phe/Phe Tyr/Tyr were studied compared. The data show a larger influence packing/surrounding, more than substituents, on geometries interactions. While CSD preference for parallel stacking at large offsets, proteins PDB, they T-shaped with offsets.