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Search The CSA
PDB ID
UNIPROT ID
EC Number

Catalytic Site Atlas

CSA LITERATURE entry for 1g8o

E.C. nameN-acetyllactosaminide 3-alpha-galactosyltransferase
SpeciesBos taurus (Bovine)
E.C. Number (IntEnz) 2.4.1.87
CSA Homologues of 1g8oThere are 75 Homologs
CSA Entries With UniProtID P14769
CSA Entries With EC Number 2.4.1.87
PDBe Entry 1g8o
PDBSum Entry 1g8o
MACiE Entry M0356

Literature Report

IntroductionAlpha-1-3-galactosyltransferase is involved in post translational modification of proteins in the golgi apparatus to form glycoproteins through the addition of a galactose sugar unit to glycan. It is found in most mammals but not humans and thus its activity may result in the rejection of transplants from pigs.
MechansimThe reaction proceeds via nucleophilic attack on the UDP galactose substrate by the catalytic residue Glu 317 to form a covalent glycosyl-enzyme intermediate. This allows the galactose to be transferred to the second substrate through nucleophilic attack by the deprotonated sugar oxygen on the anomeric carbon. The double displacement thus results in retention of configuration (alpha). The mechanism whereby the sugar oxygen is deprotonated is unclear, but seems likely to involve direct transfer of the proton to the UDP leaving group.
Reaction

Catalytic Sites for 1g8o

Annotated By Reference To The Literature - Site 1 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
GluA317317macie:sideChainAttacks the anomeric carbon of UDP galactose to form a covalent glycosyl-enzyme intermediate, allowing transfer of the galactose to the substrate.

Literature References

Notes:
Gastinel LN
Bovine alpha1,3-galactosyltransferase catalytic domain structure and its relationship with ABO histo-blood group and glycosphingolipid glycosyltransferases.
EMBO J 2001 20 638-649
PubMed: 11179209
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