A GH89 human α-N-acetylglucosaminidase (hNAGLU) homologue from gut microbe Bacteroides thetaiotaomicron capable of hydrolyzing heparosan oligosaccharides

Carbohydrate-Active enZYme (CAZY) GH89 family enzymes catalyze the cleavage of terminal alpha-N-acetylglucosamine from glycans and glycoconjugates. Although structurally and mechanistically similar to the human lysosomal alpha-N-acetylglucosaminidase (hNAGLU) in GH89 which is involved in the degradation of heparan sulfate in the lysosome, the reported bacterial GH89 enzymes characterized so far have no or low activity toward alpha-N-acetylglucosamine-terminated heparosan oligosaccharides, the preferred substrates of hNAGLU. We cloned and expressed several soluble and active recombinant bacterial GH89 enzymes in Escherichia coli. Among these enzymes, a truncated recombinant alpha-N-acetylglucosaminidase from gut symbiotic bacterium Bacteroides thetaiotaomicron increment 22Bt3590 was found to catalyze the cleavage of the terminal alpha 1-4-linked N-acetylglucosamine (GlcNAc) from a heparosan disaccharide with high efficiency. Heparosan oligosaccharides with lengths up to decasaccharide were also suitable substrates. This bacterial alpha-N-acetylglucosaminidase could be a useful catalyst for heparan sulfate analysis.

Automated summary

A study found a bacterial α-N-acetylglucosaminidase from gut symbiotic bacterium Bacteroides thetaiotaomicron, capable of efficiently cleaving N-acetylglucosamine from heparosan disaccharide. This enzyme could potentially serve as a useful catalyst for heparan sulfate analysis.