Current efforts to unravel the secrets of efficient fungal biomass conversion are hampered by the bottleneck that exists in our limited knowledge about the molecular interaction networks between the proteins/enzymes and the plant cell wall components. On the other hand, the majority of the studies, with few exceptions, use artificial substrates, focusing particularly on a specific enzymatic activity, disregarding the global protein networks, which are universally used in all metabolic pathways. In a previous study, our laboratory has reported the structural and functional characterisation of a recombinant beta-glucosidase of Trichoderma harzianum (rThBgl), which was overexpressed by this fungus under biomass degradation conditions. Attempting to improve the rThBgl catalytic properties, including thermostability and high glucose-tolerance, ThBgl-derived mutants were constructed based on structural alignment/prediction using high resolution beta-glucosidase structures available in Protein Data Bank. However, a recent data obtained by our group pointed to a possible extended activity of this enzyme; leading to some questions about the role of beta-glucosidases in the degradation of biomass. In this context, the present project aims to investigate the non-canonical enzymatic activity and synergistic relationships of ²-glucosidase from T. harzianum with other lignocellulose degrading enzymes using several substrates, including sugarcane bagasse and biomass-derived from different plant mutants affected in cell wall synthesis (altered cellulose structure, lignin composition, and xylan structure), beside others substrates available in the Plant Biochemistry Lab, Cambridge, to try work out how the enzymatic activity can be modulated by xylan interaction with cellulose microbribrils.
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