InterPro: IPR013812 Glycoside hydrolase, family 2/20, immunoglobulin-like beta-sandwich domain

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.

Glycoside hydrolase family 2 GH2 comprises enzymes with several known activities: beta-galactosidase (EC:3.2.1.23); beta-mannosidase (EC:3.2.1.25); beta-glucuronidase (EC:3.2.1.31).

Glycoside hydrolase family 20 GH20 consists of enzymes such as chitobiases and beta-hexosaminidases (EC:3.2.1.52), in which this immunoglobulin-like domain occurs at the C terminus [5, 6].

This entry describes the immunoglobulin-like beta-sandwich domain that consists of seven beta-strands in two sheets with a Greek-key topology, although some members may have extra strands. This fold is found in domains of glycoside hydrolase families 2 and 20. The function of this domain is unknown.