Computational Modelling of Catalytic Properties and Modified Substrates of Fungal β-N-Acetylhexosaminidases

Besides their implication in human physiology and disease, β-N-acetylhexosaminidases (EC 3.2.1.52, CAZy GH 20) have recently gained a lot of attention thanks to their great potential in the enzymatic synthesis of carbohydrates and glycomimetics. Extracellular β-N-acetylhexosaminidases from filamentous fungi proved to be a powerful synthetic tool for the preparation of both natural and modified glycosides under mild conditions with good yields. A homology model of β-N-acetylhexosaminidase from the filamentous fungus Aspergillus oryzae has recently been reported, and its quality was corroborated by vibrational spectroscopy and biochemical studies. Computational modelling and analysis helped to identify active site amino acids and other basic structural features of this enzyme important in the catalytic process; moreover, the surface interactions of the subunits of the glycosylated enzyme were identified. The model of β-N-acetylhexosaminidase from Aspergillus oryzae prepared the ground for further in silico studies of enzyme-substrate complexes including prediction and explanation of its substrate specificity.