Fig. 9
A phylogenetic tree of the class B metallo-β-lactamase family. MBLs can be classified into three subclasses (B1, B2, B3) based on their amino acid sequences. Subclasses B1 and B3 are characterized by two Zn2+ molecules in the enzyme active center (Zn1, Zn2), implying a broader range of substrates, whereas target substrates of subclass B2, which have a single Zn2+ at the active center, are narrower in range than those of classes 1 and 3 [54]. Based on the primary sequences, the tree was generated using Clustal Omega [32,33,34] of GenomeNet at Kyoto University Bioinformatics Center (https://www.genome.jp/tools-bin/clustalw)