| GH20 beta-N-acetylhexosamindase (Hex), one of the 125 families Glycosyl hydrolase (GH), is the intrigue of our paper. As its name implies, GH20 Hex hydrolyzes non-reducing terminalβ-linked N-acetylhexosamine residues of oligosaccharides and their conjudges. Particular interest has been paid on the versatile and wild spread enzymes. It is distributed in bacteria, early eukaryotes, fungi, plants, invertebrates and vertebrates. It is involved in important physiological processes, such as cell structural integrity, energy storage, pathogen defence, viral penetration, cellular signalling, fertilization, development of carcinomas, inflammatory events and lysosomal storage diseases. Its substrates include chitiooligosaccharides, N-glycans and glycoprotein. The cleavage could be of glucose- and galactose- configuration from (3(1,3) or (1,4) or (1,6) linkages.Nevertheless, only limited analyses of phylogenetic relationships between GH20 genes have been performed until now. In this article, sequences of GH20 Hexes are collected, combined with substrates spectrum and utilized in phylogenic analysis and sequences alignments based on advanced structures. It is revealed that GH20 Hexes could origin from different acquisitions, and they fulfill different functions with different strategies by resorting to different molecular basis. This result fits and unites most characterized GH20 Hexes in early literature. The understanding of GH20 Hexes diversity could offer information on protein engineering, and a point of view for theoretical study of other Glycosyl hydrolases diversity, as well. |
