FC0010
Cellulase E (chimera)  -  Cellulose

Biological function
Cellulases degrade cellulose

Domain organization/sequence features
QSGNPFSGRTLLVNSDYSSKLDQTRQAFLSRGDQTNAAKVKYVQEKVGTFYWISNIFLLRDIDVAIQNARAAKARGENPIVGLVLYNL PDRDCSAGESSGELKLSQNGLNRYKNEYVNPFAQKLKAA

Structural evidence
In the studied chimera assembled from Cel6A and Cel6B the catalytic modules are connected by an 88-residue linker, which is disordered based on predictions, X-ray crystallography and SAXS. The linker was experimentally shown to adopt a wide range of conformations with end-to-end distances varying from 10 to 80 Å. In the most compact state it positions the catalytic and the cellulose binding modules (CBM) to be separated by one cellulose unit. The average intermodule distance is 32 Å.

Biochemical evidence
The linker ensures that the catalytic and the CBM modules act independently. After hydrolysis, the catalytic module diffuses away and hydrolyzes another glycosidic bond, while the CBM is still attached to the surface of cellulose.

Mechanism category
tethering

Significance
The fuzzy region regulates a caterpillar like motion of the two cellulose binding modules and enables efficient hydrolysis of the substrates.