TY - JOUR
T1 - Thermoactivation of a cellobiohydrolase
AU - Westh, Peter
AU - Borch, Kim
AU - Sørensen, Trine Holst
AU - Tokin, Radina
AU - Kari, Jeppe
AU - Badino, Silke Flindt
AU - Cavaleiro, Mafalda A.
AU - Røjel, Nanna Sandager
AU - Christensen, Stefan Jarl
AU - Vesterager, Cynthia Segura
AU - Cola, Corinna Schiano di
N1 - This article has been found as a ’Free Version’ from the Publisher on January 4th 2019. When access to the article closes, please notify [email protected]
PY - 2018/1
Y1 - 2018/1
N2 - We have measured activity and substrate affinity of the thermostable cellobiohydrolase, Cel7A, from Rasamsonia emersonii over a broad range of temperatures. For the wild type enzyme, which does not have a Carbohydrate Binding Module (CBM), higher temperature only led to moderately increased activity against cellulose, and we ascribed this to a pronounced, temperature induced desorption of enzyme from the substrate surface. We also tested a "high affinity" variant of R. emersonii Cel7A with a linker and CBM from a related enzyme. At room temperature, the activity of the variant was similar to the wild type, but the variant was more accelerated by temperature and about two-fold faster around 70 °C. This better thermoactivation of the high-affinity variant could not be linked to differences in stability or the catalytic process, but coincided with less desorption as temperature increased. Based on these observations and earlier reports on moderate thermoactivation of cellulases, we suggest that better cellulolytic activity at industrially relevant temperatures may be attained by engineering improved substrate affinity into enzymes that already possess good thermostability.
AB - We have measured activity and substrate affinity of the thermostable cellobiohydrolase, Cel7A, from Rasamsonia emersonii over a broad range of temperatures. For the wild type enzyme, which does not have a Carbohydrate Binding Module (CBM), higher temperature only led to moderately increased activity against cellulose, and we ascribed this to a pronounced, temperature induced desorption of enzyme from the substrate surface. We also tested a "high affinity" variant of R. emersonii Cel7A with a linker and CBM from a related enzyme. At room temperature, the activity of the variant was similar to the wild type, but the variant was more accelerated by temperature and about two-fold faster around 70 °C. This better thermoactivation of the high-affinity variant could not be linked to differences in stability or the catalytic process, but coincided with less desorption as temperature increased. Based on these observations and earlier reports on moderate thermoactivation of cellulases, we suggest that better cellulolytic activity at industrially relevant temperatures may be attained by engineering improved substrate affinity into enzymes that already possess good thermostability.
KW - Arrhenius equation
KW - Cel7A
KW - cellulase
KW - enzyme inactivation
KW - interfacial enzyme activity
KW - optimal temperature
U2 - 10.1002/bit.26513
DO - 10.1002/bit.26513
M3 - Journal article
SN - 0006-3592
VL - 115
SP - 831
EP - 838
JO - Biotechnology and Bioengineering (Print)
JF - Biotechnology and Bioengineering (Print)
IS - 4
ER -