An enzyme (CelZ) from Clostridium stercorarium has an almost identical structure. When deleting the adherent first CBM (together with the second), the enzyme got thermolabile, i.e. it hat almost no enzymatic activity at 60 °C, however the activity could be measured at lower temperature (Riedel et al., FEMS Microbiol Let. 164:261-267 (1998)). Have the authors tried to check for activity at lets say 30°C? Or is the enzyme core bent by binding to the CBM in a way to become active at all - and stabilized? This paper seems to present a molecular explanation for data obtained in 1998 - however with a different enzyme.