3.2.1.140	evolution	LnbB is a member of the glycoside hydrolase family 20, GH20	753153	
3.2.1.140	evolution	LnbX is a non-classified member of the glycoside hydrolase family	753153	
3.2.1.140	evolution	the enzyme belongs to the glycoside hydrolase family 20, GH20	732092	
3.2.1.140	evolution	the enzyme belongs to the glycosyl hydrolase family 20, GH20	753245	
3.2.1.140	evolution	the enzyme belongs to the glycosyl hydrolase family 20, GH20. Domain organization of GH20 beta-N-acetylhexosaminidases, overview	755088	
3.2.1.140	evolution	the LnbX protein is found only in Bifidobacterium bifidum, Bifidobacterium longum, and a few gut microbes, suggesting that the protein has evolved in specialized niches	-, 732113	
3.2.1.140	metabolism	the enzyme is critical in the lacto-N-biose pathway	731652	
3.2.1.140	metabolism	the enzyme liberates lacto-N-biose I, i.e. Gal-beta-(1->3)-GlcNAc, the major core structure, from the nonreducing end of human milk oligosaccharides and plays a key role in the metabolic pathway of these compounds	732092	
3.2.1.140	additional information	the enzyme reaction proceeds via a substrate-assisted catalytic mechanism. The enzyme consists of three domains, and the C-terminal domain has a unique beta-trefoil-like fold. Compared with other beta-N-acetylhexosaminidases, lacto-N-biosidase has a wide substrate-binding pocket with a -2 subsite specific for beta-1,3-linked Gal, three-dimensional structure and possible conformational pathway for the lacto-N-biosidase reaction, overview. Enzyme structure and active site structure comparisons. The two catalytic residues of GH20, Asp320 (polarizing residue) and Glu321 (acid/base catalytic residue), form hydrogen bonds with the amide nitrogen of the 2-acetamido group and the O1-hydroxyl,respectively. Tyr-419 is a highly conserved residue in GH20 enzymes, and its side-chain hydroxyl group forms a hydrogen bond with the carbonyl oxygen atom of the 2-acetamido group. Asp467 forms bifurcated hydrogen bonds with the O4- and O6-hydroxyl groups of the GlcNAc residue. Catalytic reaction mechanism and conformational changes analysis	732092	
3.2.1.140	additional information	the large Bifidobacterium bifidum lacto-N-biosidase and its truncated mutants are used as model proteins to evaluate the minimal functional unit due to its interest and structural complexity. Structure-function analysis of the wild-type in comparison to different truncated enzyme mutants, and comparisons of enzyme structure models, overview. The lacto-N-biosidase requires GH20b and the lectin-like domain at the N- and C-termini of the catalytic GH20 domain to be fully soluble and functional. The lectin domain provides this remote element to the active site. Restoration of activity of the inactive GH20beta-GH20-alpha construct (model A architecture) by a complementation assay with the lectin-like domain	755088