Angles between the Zn atom and its coordinating atoms^a.

aMean values and standard deviations are in degrees. bFor the crystal structures, the angle between the Zn-coordinating oxygen atoms of the bound inhibitor was measured, for the apo simulation the angle between the Zn-coordinating oxygen atoms of the two proximal water molecules was measured, and for the ligand-bound simulation, the angle between the Zn-coordinating oxygen atoms of the nucleophilic water and the ligand carbonyl oxygen atom was measured. cMean values and standard deviations obtained by averaging over 9 PDB structures of aminopeptidase N: P. falciparum (3EBH, 3EBI, 3EBG; [15]), E. coli (2ZXG; [24]), E. coli (2HPT, 2HPO; [17]), E. coli (2DQM, 2DQ6; [16]), N. meningitidis (2GTQ, [18]). The protein atom-Zn angles are the means of 9 measurements, the water 1 angle is the mean distances measured from 4 unliganded structures. The O-Zn-O angle is the mean from 5 inhibitor-bound structures. dFrom PfA-M1 simulations, angles sampled every 50 ps over the 75 ns simulations.