glycosyl hydrolase family 16. The O-Glycosyl hydrolases 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 glycosyl hydrolase classification system based on sequence similarity has led to the definition of more than 95 different families inlcuding glycosyl hydrolase family 16. Family 16 includes lichenase, xyloglucan endotransglycosylase (XET), beta-agarase, kappa-carrageenase, endo-beta-1,3-glucanase, endo-beta-1,3-1,4-glucanase, and endo-beta-galactosidase, all of which have a conserved jelly roll fold with a deep active site channel harboring the catalytic residues.

lichenase, member of glycosyl hydrolase family 16. Lichenase, also known as 1,3-1,4-beta-glucanase, is a member of glycosyl hydrolase family 16, that specifically cleaves 1,4-beta-D-glucosidic bonds in mixed-linked beta glucans that also contain 1,3-beta-D-glucosidic linkages. Natural substrates of beta-glucanase are beta-glucans from grain endosperm cell walls or lichenan from the Islandic moss, Cetraria islandica. This protein is found not only in bacteria but also in anaerobic fungi. This domain includes two seven-stranded antiparallel beta-sheets that are adjacent to one another forming a compact, jellyroll beta-sandwich structure.

Probable xyloglucan endotransglucosylase/hydrolase protein; Provisional

Glycosyl hydrolases family 16.

Xyloglucan endotransglycosylase, member of glycosyl hydrolase family 16. Xyloglucan endotransglycosylases (XETs) cleave and religate xyloglucan polymers in plant cell walls via a transglycosylation mechanism. Xyloglucan is a soluble hemicellulose with a backbone of beta-1,4-linked glucose units, partially substituted with alpha-1,6-linked xylopyranose branches. It binds noncovalently to cellulose, cross-linking the adjacent cellulose microfibrils, giving it a key structural role as a matrix polymer. Therefore, XET plays an important role in all plant processes that require cell wall remodeling.