Three-dimensional structure of the recombinant ‘AcTesA. a) Overall structure of ‘AcTesA. The indicated residues are the catalytic triad, Ser10-Asp158-His161, and the stabilizing oxyanion residues, Gly48 and Asn77. b) Stereo view (Swiss-pdbviewer) of the catalytic triad and the oxyanion residues. The dashed lines indicate hydrogen bonding network, and the values represent the atom-atom distances.