FIG 3.

(A) Electron density from the final omit map corresponding to moxalactam covalently bound to Ser62 is shown as a blue wire contoured at 3 σ. The BEL-1 residues corresponding to the four motifs described in the legend to Fig. 1 are shown as sticks by following the same color code. (B) H bonds involving moxalactam within the BEL-1 active site. The residue colors follow the above-described scheme. The short H-bond distance between the carboxylate of Glu159 and the deacylating water (Wat) is indicated.