Glycosyl transferase, family 43 (IPR005027)

Short name: Glyco_trans_43

Overlapping homologous superfamilies

Family relationships



The biosynthesis of disaccharides, oligosaccharides and polysaccharides involves the action of hundreds of different glycosyltransferases. These enzymes catalyse the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. A classification of glycosyltransferases using nucleotide diphospho-sugar, nucleotide monophospho-sugar and sugar phosphates ([intenz:2.4.1.-]) and related proteins into distinct sequence based families has been described [PMID: 9334165]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site. The same three-dimensional fold is expected to occur within each of the families. Because 3-D structures are better conserved than sequences, several of the families defined on the basis of sequence similarities may have similar 3-D structures and therefore form 'clans'.

Glycosyltransferase family 43 GT43 comprises enzymes with only one known activity: beta-glucuronyltransferase(GlcAT-I; EC: [PMID: 10358066].

GlcAT-I is a key enzyme involved in the initial steps of proteoglycan synthesis [PMID: 10526176]. GlcAT-I catalyzes the transfer of a glucuronic acid moiety from the uridine diphosphate-glucuronic acid (UDP-GlcUA) to the common linkage region of trisaccharide Gal-beta-(1-3)-Gal-beta-(1-4)-Xyl of proteoglycans. The enzyme has two subdomains that bind the donor and acceptor substrate separately [PMID: 10521532]. The active site is located at the cleft between both subdomains in which the trisaccharide molecule is oriented perpendicular to the UDP [PMID: 10508766].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0015018 galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase activity

Cellular Component

GO:0016020 membrane

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.