Fig. 4: Illustration of the effect of the non-catalytic CBM (a) and tryptophan residues in the catalytic domain of cellobiohydrolases from GH6 and GH7 (b).
From: Physical constraints and functional plasticity of cellulases
a Correlation plot of ln(KM) and ln(kcat) for three wild-type CBHs and three variants, where the CBM was either removed (−CBM) from the wild-type (TrCel7A → TrCel7ACD, TrCel6A → TrCel6ACD) or added (+CBM) to the wild type (ReCel7A → ReCel7ACBM). b Analogous correlation plot for replacements of conserved tryptophan residues by alanine in the catalytic domain of TrCel7A (TrCel7A → TrCel7AW38A) or TrCel6A (TrCel6A → TrCel6AW269A). The solid line shown in both plots is the same as in Fig. 2. It appears that changes in KM and kcat tend to compensate so that all enzymes remain close to the diagonal. Inserts are illustrations to guide the reader about the structural changes in the variants. Error bars represent standard deviations from MM-fit (Eq. 2) to triplicates.
