InterPro: IPR019563 Glycoside hydrolase 97

O-Glycosyl hydrolases EC:3.2.1. are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycosyl hydrolases, based on sequence similarity, has led to the definition of 85 different families [1, 2, 3]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site [4]. Because the fold of proteins is better conserved than their sequences, some of the families can be grouped in clans.

This is the 97th family of glycosidases, in this case bacterial. The central part of the GH97 family protein sequences represents a typical and complete (beta/alpha)8-barrel or catalytic TIM-barrel type domain. The N- and C-terminal parts of the sequences, mainly consisting of beta-strands, most probably form two additional non-catalytic domains with as yet unknown functions. The non-catalytic domains of glycosidases from the alpha-galactosidase and alpha-glucosidase superfamilies are also predominantly composed of beta-strands, and at least some of these domains are involved in oligomerisation and carbohydrate binding. In all known glycosidases with the (beta-alpha)8-barrel fold, the amino acid residues at the active site are located on the C-termini of the beta-strands [5].