PDBsum entry 2o1h

Transferase

PDB id: 2o1h

Contents

Protein chain

262 a.a. *

Ligands

UDP

Metals

_HG ×5

_MN

Waters ×236

* Residue conservation analysis

PDB id:

2o1h

Name:

Transferase

Title:

Naturally occurring mutation of humna abo(h) galactosyltransferase in complex with udp: gtb/m214t_udp

Structure:

Abo glycosyltransferase. Chain: a. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: abo. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693.

Resolution:

1.67Å R-factor: 0.178 R-free: 0.222

Authors:

J.A.Letts,S.N.Borisova,S.V.Evans

Key ref:

M.Persson et al. (2007). Structural effects of naturally occurring human blood group B galactosyltransferase mutations adjacent to the DXD motif. J Biol Chem, 282, 9564-9570. PubMed id: 17259183 DOI: 10.1074/jbc.M610998200

Date:

28-Nov-06 Release date: 06-Feb-07

Protein chain

P16442  (BGAT_HUMAN) -  Histo-blood group ABO system transferase from Homo sapiens

Seq: 354 a.a.

Struc: 262 a.a.*

* PDB and UniProt seqs differ at 7 residue positions (black crosses)

Enzyme reactions

• Enzyme class 1: E.C.2.4.1.37 - fucosylgalactoside 3-alpha-galactosyltransferase.
• Reaction: an alpha-L-fucosyl-(1->2)-beta-D-galactosyl derivative + UDP-alpha-D- galactose = an alpha-D-galactosyl-(1->3)-[alpha-L-fucosyl-(1->2)]-beta-D- galactosyl derivative + UDP + H⁺

alpha-L-fucosyl-(1->2)-beta-D-galactosyl derivative + UDP-alpha-D- galactose = alpha-D-galactosyl-(1->3)-[alpha-L-fucosyl-(1->2)]-beta-D- galactosyl derivative + UDP + H(+) (Bound ligand (Het Group name = UDP) corresponds exactly)

• Enzyme class 2: E.C.2.4.1.40 - glycoprotein-fucosylgalactoside alpha-N-acetylgalactosaminyltransferase.
• Reaction: an alpha-L-fucosyl-(1->2)-beta-D-galactosyl derivative + UDP-N-acetyl- alpha-D-galactosamine = an N-acetyl-alpha-D-galactosaminyl-(1->3)-[alpha- L-fucosyl-(1->2)]-beta-D-galactosyl derivative + UDP + H⁺

alpha-L-fucosyl-(1->2)-beta-D-galactosyl derivative + UDP-N-acetyl- alpha-D-galactosamine = N-acetyl-alpha-D-galactosaminyl-(1->3)-[alpha- L-fucosyl-(1->2)]-beta-D-galactosyl derivative + UDP + H(+) (Bound ligand (Het Group name = UDP) corresponds exactly)

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Added reference

DOI no: 10.1074/jbc.M610998200

J Biol Chem 282:9564-9570 (2007)

PubMed id: 17259183

Structural effects of naturally occurring human blood group B galactosyltransferase mutations adjacent to the DXD motif.

M.Persson, J.A.Letts, B.Hosseini-Maaf, S.N.Borisova, M.M.Palcic, S.V.Evans, M.L.Olsson.

ABSTRACT

Human blood group A and B antigens are produced by two closely related glycosyltransferase enzymes. An N-acetylgalactosaminyltransferase (GTA) utilizes UDP-GalNAc to extend H antigen acceptors (Fuc alpha(1-2)Gal beta-OR) producing A antigens, whereas a galactosyltransferase (GTB) utilizes UDP-Gal as a donor to extend H structures producing B antigens. GTA and GTB have a characteristic (211)DVD(213) motif that coordinates to a Mn(2+) ion shown to be critical in donor binding and catalysis. Three GTB mutants, M214V, M214T, and M214R, with alterations adjacent to the (211)DVD(213) motif have been identified in blood banking laboratories. From serological phenotyping, individuals with the M214R mutation show the B(el) variant expressing very low levels of B antigens, whereas those with M214T and M214V mutations give rise to A(weak)B phenotypes. Kinetic analysis of recombinant mutant GTB enzymes revealed that M214R has a 1200-fold decrease in k(cat) compared with wild type GTB. The crystal structure of M214R showed that DVD motif coordination to Mn(2+) was disrupted by Arg-214 causing displacement of the metal by a water molecule. Kinetic characterizations of the M214T and M214V mutants revealed they both had GTA and GTB activity consistent with the serology. The crystal structure of the M214T mutant showed no change in DVD coordination to Mn(2+). Instead a critical residue, Met-266, which is responsible for determining donor specificity, had adopted alternate conformations. The conformation with the highest occupancy opens up the active site to accommodate the larger A-specific donor, UDP-GalNAc, accounting for the dual specificity.

Selected figure(s)

Figure 3.
FIGURE 3. Electron density surrounding Met-266 in M214T, showing the alternate conformations that this residue adopts. Electron density is contoured at 1.00 (cyan) and 2.50 (blue). The major conformation is shown in green and the minor conformations in yellow and magenta. Atoms are colored by element: carbon, white; oxygen, red; nitrogen, blue; sulfur, yellow.

Figure 5.
FIGURE 5. a, wild type GTB showing the position of Met-214 and Met-266 relative to bound UDP-Gal. b, M214T showing the position of Thr-214 and Met-266 relative to bound UDP-Gal. The predominant conformation of Met-266 (green) opens up the active site. c, M214T modeled with UDP-GalNAc. The larger A-donor, UDP-GalNAc, can be accommodated by the high occupancy conformation of Met-266 (green) and not the low occupancy, wild type conformation (yellow). Atoms are colored by element: carbon, white; oxygen, red; nitrogen, blue; sulfur/phosphorous, yellow. The modeled Gal and GalNAc of the donors are shown with magenta bonds.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2007, 282, 9564-9570) copyright 2007.

Figures were selected by an automated process.