Figure 3
From: Theoretical study on the polar hydrogen-π (Hp-π) interactions between protein side chains
The Hp-π interaction structures and HOMOs of three aromatic interaction pairs. (A) Structure of Hp-π interaction pair CH3OH-C6H6. The polar hydrogen atom of CH3OH points to the center of C6H6 perpendicularly. (B) The HOMO of Hp-π interaction pair CH3OH-C6H6. The polar hydrogen atom is in close touching with the π-orbital of C6H6. (C) Structure of Hp-π interaction pair CH3OH-C5H5N. The polar hydrogen atom of CH3OH points to the N of C5H5N. (D) The HOMO of Hp-π interaction pair CH3OH-C5H5N. (E) Structure of Hp-π interaction pair NMA-C6H6. The polar hydrogen atom of NMA (n-methyl acetamide) points to the center of C6H6 perpendicularly. (F) The HOMO of Hp-π interaction pair NMA-C6H6.