Fig. 4

Effect of linker inserted between enzyme and dockerin module. A. Effect of different linkers inserted between T. fusca mannanase and A. cellulolyticus dockerin on the activity of mannanase docking enzymes. The activity of Tf-Manna-Li (construct nr. 3), Tf-Manna-Li_Doc-Ac (construct nr. 13), variants of Tf-Manna-Li and Doc-Ac with linkers E–H (constructs nr. 24, 25, 26 and 27), Tf-Manna (construct nr. 2), Tf-Manna_Doc-Ac (construct nr. 19) and variants of Tf-Manna and Doc-Ac with linkers E–H (constructs nr. 20, 21, 22 and 23) are shown. Reaction mixtures were composed of 1 mL 0.5% GM and 10 pmol enzyme. B. Effect of different linkers inserted between C. japonicus galactosidase and C. thermocellum type I dockerin on the activity of galactosidase docking enzymes. The activity of Cj-Aga (construct nr. 55), Cj-Aga_Doc-CtI (construct nr. 56), variants of Cj-Aga and Doc-CtI with linkers A-D (constructs nr. 60, 61, 62 and 63) are shown. Reaction mixtures were composed of 1 mL 0.5% GM and 48 pmol enzyme. Enzymatic activity was determined quantitatively by measuring the released reducing sugars with the DNS method. All slopes were converted to enzymatic activity (U/nmol). Each bar represents the mean ± SD of three replicates. Docking enzymes with linker were compared to the docking enzyme without a linker. *p < 0.1, Student’s t-test; **p < 0.05, Student’s t-test