FIG 2.

PpgL is a metal-independent gluconolactonase. (A) Hypothetical reaction that PpgL catalyzes in P. aeruginosa. (B) Relative activity of PpgL in the presence of 2.5 mM concentrations of different metal ions or EDTA. Activity was measured using d-glucono-δ-lactone as the substrate. Each bar represents the mean of three independent measurements (±SEM). ns, not significant. (C) The metal binding sites of different metal-dependent/-independent lactone-forming/-hydrolyzing enzymes, including Drp35 (PDB 2DG1) from Staphylococcus aureus (i), Vgb (PDB 2Z2P) from Staphylococcus aureus (ii), SMP30 (PDB 3G4H) from Homo sapiens (iii), mSMP30 (PDB 4GN9) from Mus musculus (iv), NcCMLE (PDB 1JOF) from Neurospora crassa (v), and PpgL (PDB 6IGB) (vi).