Fig. 1: Sequence analysis of GH57 family members and enzyme activity of AaApu.

a Five conserve regions of GH57 from different strains, AaApu is amylopullulanase from Aquifex aeolicus; BAA22063.1 is the 4-α-glucanotransferase from Thermococcus litoralis DSM 5473; BAD71725.1, BAA30492.1 and BAD85625.1 are the α-1,4-glucan branching enzyme from Thermococcus kodakarensis KOD1, Pyrococcus horikoshii and Thermus thermophilus HB8, respectively. AAD28552.1 and BAC10983.1 are amylopullulanases from Thermococcus hydrothermalis and Thermococcus litoralis, respectively. Catalytic residues are highlighted with red boxes. b Effect of pH on the enzyme activity of AaApu. c Effect of temperature on the enzyme activity of AaApu wild-type (black), E256Q (blue), E256L (green), and D352N (purple). Data are expressed as mean ± SEM (n = 3).