Figure 5

Determination of the active-site residues of ‘AcTesA by site-directed mutagenesis. FFAs productin (a) and cell densities (b) of the wild-type strain BL21(DE3) (control) and the recombinant strains (‘AcTesA, S10A, G48A, N77A, D158A and H161A). Compared with the native ‘AcTesA, the mutation to Ala at Ser¹⁰ (S10A), Gly⁴⁸ (G48A), Asp¹⁵⁸ (D158A) and His¹⁶¹ (H161A) residues led to totally loss of the thioesterase activity, and the mutation to Ala at Asn⁷⁷ (N77A) residue caused the substantial decrease of the enzyme activity. The error bars represent the range from two independent experiments.