Figure 1.

Structure of BaP1 and location of the catalytic zinc and the substrate binding subsites. (A) The catalytic zinc ion is coordinated tetrahedrally by the N$ϵ$2 atoms of three histidine residues (His142, His146, His 152) and the oxygen atom of the catalytic water molecule (Wat67), coordinated by the residue Glu143. The Zn${}^{2+}$ ion is shown as a gray sphere. The indicated amino acids are shown in a bond representation (H, white; C, gray; N, blue; O, red). (B) The side chains of amino acids belonging to the substrate binding subsites indicated by color: S1, red; S1${}^{\prime }$, magenta; S2${}^{\prime }$, blue; S3${}^{\prime }$, green. (C) Surface of BaP1 showing the substrate binding subsites with the color code previously described. Coordinates of BaP1 were obtained from the Protein Data Bank (PDB code 2W15).