Zinc Beta-lactamase superfamily

The metallo-beta-lactamase superfamily was first defined in 1997 on the basis of a sequence alignment. The members of this superfamily are characterized by the presence of a common alpha-beta-beta-alpha fold and share five conserved motifs: Asp84, His116-Xaa-His118-Xaa-Asp120-His121, His196, Asp221 and His263, which are (with the exception of Asp84) involved in the binding of two metal ions. This superfamily contains now more than 23,900 members divided into 17 biological groups. Besides metallo-beta-lactamases which cleave the amide bond of the β-lactam ring of penicillins, cephalosporins or carbapenems (thus inactivating the antibiotic), the metallo-beta-lactamase superfamily includes enzymes which hydrolyze thiol-ester, phosphodiester and sulfuric ester bonds as well as oxydoreductases.