1XZ6

Mutant ABO(H) blood group glycosyltransferase A

Summary for 1XZ6

• Entry DOI: 10.2210/pdb1xz6/pdb
• Related: 1LZ0
• Descriptor: Histo-blood group ABO system transferase, MERCURY (II) ION (3 entities in total)
• Functional Keywords: rossman nucleotide binding fold, transferase
• Biological source: Homo sapiens (human)
• Cellular location: Golgi apparatus, Golgi stack membrane; Single-pass type II membrane protein: P16442
• Total number of polymer chains: 1
• Total formula weight: 34949.82

Authors

Lee, H.J.,Barry, C.H.,Borisova, S.N.,Seto, N.O.L.,Zheng, R.B.,Blancher, A.,Evans, S.V.,Palcic, M.M. (deposition date: 2004-11-11, release date: 2004-12-07, Last modification date: 2024-02-14)

Primary citation

Lee, H.J.,Barry, C.H.,Borisova, S.N.,Seto, N.O.L.,Zheng, R.B.,Blancher, A.,Evans, S.V.,Palcic, M.M.
Structural basis for the inactivity of human blood group O2 glycosyltransferase
J.Biol.Chem., 280:525-529, 2005

PubMed Abstract: The human ABO(H) blood group antigens are carbohydrate structures generated by glycosyltransferase enzymes. Glycosyltransferase A (GTA) uses UDP-GalNAc as a donor to transfer a monosaccharide residue to Fuc alpha1-2Gal beta-R (H)-terminating acceptors. Similarly, glycosyltransferase B (GTB) catalyzes the transfer of a monosaccharide residue from UDP-Gal to the same acceptors. These are highly homologous enzymes differing in only four of 354 amino acids, Arg/Gly-176, Gly/Ser-235, Leu/Met-266, and Gly/Ala-268. Blood group O usually stems from the expression of truncated inactive forms of GTA or GTB. Recently, an O(2) enzyme was discovered that was a full-length form of GTA with three mutations, P74S, R176G, and G268R. We showed previously that the R176G mutation increased catalytic activity with minor effects on substrate binding. Enzyme kinetics and high resolution structural studies of mutant enzymes based on the O(2) blood group transferase reveal that whereas the P74S mutation in the stem region of the protein does not appear to play a role in enzyme inactivation, the G268R mutation completely blocks the donor GalNAc-binding site leaving the acceptor binding site unaffected.

PubMed: 15475562
DOI: 10.1074/jbc.M410245200

Experimental method

X-RAY DIFFRACTION (1.55 Å)