The structure also shows an atypical oxyanion hole and a partially collapsed S1 specificity pocket.

The rising pH converts oxyanion sorption sites from positive to negative releasing As (and Mo) to pore waters.

X-ray crystal structures of L29I PFE with and without bound acetate show an unusual mixture of two different oxyanion loop conformations.

The oxyanion hole hydrogen bonds provide additional stabilization for acyl-ester bond in the acyl-enzyme than for scissile peptide bond of the Michaelis complex.

Microbial oxygen production during reduction of oxyanions may enhance biodegradation of pollutants under anoxic conditions.