Structural and Functional Analysis of the Complex between Citrate and the Zinc Peptidase Carboxypeptidase A

Figure 1

Partial view of the carboxypeptidase-Zn²⁺-citrate complex structure localized around the citrate ligand. The ligand is coloured green while protein atoms are in grey. Oxygen and nitrogen atoms are red and blue, respectively. The Zn²⁺ ion is depicted as a sphere in yellow. Relevant residues for binding are shown as sticks and labelled. Polar interactions are shown as solid lines in black. The 2F_o-F_c map, calculated by deleting citrate and Zn²⁺ coordinates, is contoured at 1.0 sigma (gold mesh).