Fig. 4.

Mapping of the nitrated tyrosine residues on the crystal structure (PDB 6NFN) of the Fab fragment of the h2E2 anti-cocaine mAb co-crystallized with benzoylecgonine (BE). The structure is shown in space filling mode, with the ligand binding site pointed upwards towards the observer. Note the proximity of the light chain Y34 residue (all nitrated tyrosine residues are shown in purple color) to the bound BE ligand, and particularly to the carboxylate moiety (COOH) of the BE molecule, which protrudes up and out of the binding site, resulting in no mAb Fab protein-BE ligand carboxylate contacts in the published crystal structure. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)