N-terminal domain of Chondroitin polymerase functions as a GalNAc transferase. Chondroitin polymerase is a two domain, bi-functional protein. The N-terminal domain functions as a GalNAc transferase. The bacterial chondroitin polymerase catalyzes elongation of the chondroitin chain by alternatively transferring the GlcUA and GalNAc moiety from UDP-GlcUA and UDP-GalNAc to the non-reducing ends of the chondroitin chain. The enzyme consists of N-terminal and C-terminal domains in which the two active sites catalyze the addition of GalNAc and GlcUA, respectively. Chondroitin chains range from 40 to over 100 repeating units of the disaccharide. Sulfated chondroitins are involved in the regulation of various biological functions such as central nervous system development, wound repair, infection, growth factor signaling, and morphogenesis, in addition to its conventional structural roles. In Caenorhabditis elegans, chondroitin is an essential factor for the worm to undergo cytokinesis and cell division. Chondroitin is synthesized as proteoglycans, sulfated and secreted to the cell surface or extracellular matrix.

Glycosyltransferase, GT2 family [Carbohydrate transport and metabolism].

Subfamily of Glycosyltransferase Family GT2 of unknown function. GT-2 includes diverse families of glycosyltransferases with a common GT-A type structural fold, which has two tightly associated beta/alpha/beta domains that tend to form a continuous central sheet of at least eight beta-strands. These are enzymes that catalyze the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. Glycosyltransferases have been classified into more than 90 distinct sequence based families.

N-terminal domain of galactosyltransferase. This is the N-terminal domain of a family of galactosyltransferases from a wide range of Metazoa with three related galactosyltransferases activities, all three of which are possessed by one sequence in some cases. EC:2.4.1.90, N-acetyllactosamine synthase; EC:2.4.1.38, Beta-N-acetylglucosaminyl-glycopeptide beta-1,4- galactosyltransferase; and EC:2.4.1.22 Lactose synthase. Note that N-acetyllactosamine synthase is a component of Lactose synthase along with alpha-lactalbumin, in the absence of alpha-lactalbumin EC:2.4.1.90 is the catalyzed reaction.

Beta-4-Galactosyltransferase is involved in the formation of the poly-N-acetyllactosamine core structures present in glycoproteins and glycosphingolipids. Beta-4-Galactosyltransferase transfers galactose from uridine diphosphogalactose to the terminal beta-N-acetylglucosamine residues, hereby forming the poly-N-acetyllactosamine core structures present in glycoproteins and glycosphingolipids. At least seven homologous beta-4-galactosyltransferase isoforms have been identified that use different types of glycoproteins and glycolipids as substrates. Of the seven identified members of the beta-1,4-galactosyltransferase subfamily (beta1,4-Gal-T1 to -T7), b1,4-Gal-T1 is most characterized (biochemically). It is a Golgi-resident type II membrane enzyme with a cytoplasmic domain, membrane spanning region, and a stem region and catalytic domain facing the lumen.

Crystalstructure of chondroitin polymerase from Escherichia coli strain K4 (K4CP) complexed with UDP-GlcUA and UDP [Escherichia coli],2Z86_B Crystal structure of chondroitin polymerase from Escherichia coli strain K4 (K4CP) complexed with UDP-GlcUA and UDP [Escherichia coli],2Z86_C Crystal structure of chondroitin polymerase from Escherichia coli strain K4 (K4CP) complexed with UDP-GlcUA and UDP [Escherichia coli],2Z86_D Crystal structure of chondroitin polymerase from Escherichia coli strain K4 (K4CP) complexed with UDP-GlcUA and UDP [Escherichia coli]

Crystalstructure of chondroitin polymerase from Escherichia coli strain K4 (K4CP) complexed with UDP-GalNAc and UDP [Escherichia coli],2Z87_B Crystal structure of chondroitin polymerase from Escherichia coli strain K4 (K4CP) complexed with UDP-GalNAc and UDP [Escherichia coli]

Hyaluronan synthase OS=Pasteurella multocida OX=747 GN=hyaD PE=1 SV=2

Chondroitin synthase OS=Pasteurella multocida (strain Pm70) OX=272843 GN=fcbD PE=3 SV=1

Chondroitin synthase OS=Escherichia coli OX=562 GN=kfoC PE=1 SV=1