Fig 2.

Specific activity of PelA and variants catalyzing the hydrolysis of p-nitrophenyl acetate. Assays contained 2.5 mM p-nitrophenyl acetate, dissolved in ethanol, and ∼40 μg of wild-type PelA (WT) or one of its variants (D528A, D530A, H600A, or H604A) in a total volume of 200 μl of 50 mM sodium HEPES buffer (pH 8.0) at 25°C. To test the metal dependency of the reaction, the wild-type protein was preincubated with EDTA and assayed (WT+EDTA). Error bars represent the standard errors of the means (SEM).