An NH3+...phenyl interaction in L-phenylalanyl-L-valine.

One of the amino H atoms of L-phenylalanyl-L-valine, C(14)H(20)N(2)O(3), participates in a rare secondary interaction in being accepted by the aromatic ring of the phenylalanine side chain. The phenyl group is also a donor in a weak hydrogen bond to the peptide carbonyl group.