FIG 1.

Mutated residues in clinically derived IMP-1 gene subfamily. In total, 20 members of IMP-1-like variants were selected from IMP-1 to IMP-80. The amino acid changes acquired with respect to the sequence of the ancestor are indicated in the branches (the standard numbering scheme for class B β-lactamases were used in this study [72]). IMP-A, which is not a clinical variant, was generated in order to construct double mutant IMP-52. This figure does not describe ancestral relationships but rather illustrates the construction method for the expression plasmids used here.