InterPro: IPR019834 Glycoside hydrolase, family 8, conserved site

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 8 GH8 comprises enzymes with several known activities; endoglucanase (EC:3.2.1.4); lichenase (EC:3.2.1.73); chitosanase (EC:3.2.1.132). These enzymes were formerly known as cellulase family D [5].

The most conserved region in these enzymes is a stretch of about 20 residues that contains two conserved aspartates. The first asparatate is thought [6] to act as the nucleophile in the catalytic mechanism. This region as a signature pattern in this entry.