Expression, characterization and homology modeling of a novel eukaryotic GH84 β-N-acetylglucosaminidase from Penicillium chrysogenum

β-N-acetylglucosaminidases from the family 84 of glycoside hydrolases form a small group of glycosidases in eukaryotes responsible for the modification of nuclear and cytosolic proteins with O-GlcNAc, thus they are involved in a number of important cell processes. Here, the first fungal β-N-acetylglucosaminidase from Penicillium chrysogenum was expressed in Pichia pastoris and secreted into the media, purified and characterized. Moreover, homology modeling and substrate and inhibitor docking were performed to obtain structural information on this new member of the GH84 family. Surprisingly, we found that this fungal β-N-acetylglucosaminidase with its sequence and structure perfectly fitting to the GH84 family displays biochemical properties rather resembling the β-N-acetylhexosaminidases from the family 20 of glycoside hydrolases. This work helped to increase the knowledge on the scarcely studied glycosidase family and revealed a new type of eukaryotic β-N-acetylglucosaminidase.