Stacking interaction between uracil nuclobase and phenylalanine amino acid in the presence of anion

The π-rings are involved in diverse types of π-interactions [1] such as π-π, H-π [2], cation-π and anion-π interactions. Understanding theses interactions are essential for studying protein structures, nucleic acid structures and crystal packing [3]. In comparison with other π-interactions, the anion-π interactions have been investigated very recently [4-6]. The effect of Cl- anion on the uracil-phenylalanine (U:PHE) interaction, and vice versa, has been considered in the present work.