The filamentous fungus, Trichoderma reesei produces all of the enzymatic activities required for efficient hydrolysis of highly ordered crystalline cellulose. All the principal enzymes involved in cellulose hydrolysis possess two functional domains, one directly involved in catalysis and the other in substrate recognition and binding. The availability of high-resolution three dimensional structures of the two domains allows genetic engineering to be used for detailed structure-function studies of these important enzymes.
Teeri, T., Reinikainen, T., Ruohonen, L., Jones, A., & Knowles, J. (1992). Domain function in Trichoderma reesei cellobiohydrolases. Journal of Biotechnology, 24(2), 169-176. https://doi.org/10.1016/0168-1656(92)90120-X