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Search The CSA
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Catalytic Site Atlas

CSA LITERATURE entry for 1vzx

E.C. nameN-acetyllactosaminide 3-alpha-galactosyltransferase
SpeciesBos taurus (Bovine)
E.C. Number (IntEnz) 2.4.1.87
CSA Homologues of 1vzxThere are 64 Homologs
CSA Entries With UniProtID P14769
CSA Entries With EC Number 2.4.1.87
PDBe Entry 1vzx
PDBSum Entry 1vzx
MACiE Entry M0356

Literature Report

Introductionalpha-1,3-galactosetransferase catalyses the transfer of galactose from UDP-alpha-D-galactose into an alpha-1,3 linkage with beta-galactosyl groups in glycoconjugates. It belongs to the family of metal-dependent retaining glycosyltransferase.
The enzyme is found in many mammals, including most primates and New World monkeys but not in Old World primates, including human beings due to a mutational inactivation of its gene. Therefore, the product, alpha-galactose epitope, is the target of a large fraction of natural antibodies.
MechansimThe mechanism follows a single step SNi reaction, in which hydrolysis of UDP-galactose occurs to form a galactose with an oxycarbenium ion character, which is stabilised by Glu317. The transition state is further stabilised by Arg365, Trp314 and Manganese ion. The galactose is transferred to the acceptor substrate by a nucleophilic attack of the hydroxyl group of its anomeric carbon to the oxycarbenium ion.
Reaction

Catalytic Sites for 1vzx

Annotated By Reference To The Literature - Site 3 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
GluA317317macie:sideChainIt stabilises the cationic transition state with oxocarbenium ion character.
[EVIDENCE]
TyrA314314macie:sideChainIt stabilises the transition state in the galactose transfer
ArgA365365macie:sideChainIt stabilises the transition state of the reaction.

Annotated By Reference To The Literature - Site 4 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
GluB1317317macie:sideChainIt stabilises the cationic transition state with oxocarbenium ion character.
[EVIDENCE]
ArgB1365365macie:sideChainIt stabilises the transition state of the reaction.
TyrB1314314macie:sideChainIt stabilises the transition state in the galactose transfer

Literature References

Notes:
Zhang Y
Roles of individual enzyme-substrate interactions by alpha-1,3-galactosyltransferase in catalysis and specificity.
Biochemistry 2003 42 13512-13521
PubMed: 14621997
Boix E
Structural basis of ordered binding of donor and acceptor substrates to the retaining glycosyltransferase, alpha-1,3-galactosyltransferase.
J Biol Chem 2002 277 28310-28318
PubMed: 12011052
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
Boix E
Structure of UDP complex of UDP-galactose:beta-galactoside-alpha -1,3-galactosyltransferase at 1.53-A resolution reveals a conformational change in the catalytically important C terminus.
J Biol Chem 2001 276 48608-48614
PubMed: 11592969
Zhang Y
Roles of active site tryptophans in substrate binding and catalysis by alpha-1,3 galactosyltransferase.
Glycobiology 2004 14 1295-1302
PubMed: 15229192
Zhang Y
Specificity and mechanism of metal ion activation in UDP-galactose:beta -galactoside-alpha -1,3-galactosyltransferase.
J Biol Chem 2001 276 11567-11574
PubMed: 11133981
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