› 1o23

X-ray diffraction
2.32Å resolution

CRYSTAL STRUCTURE OF LACTOSE SYNTHASE IN THE PRESENCE OF UDP-GLUCOSE

Released:
DOI: 10.2210/pdb1o23/pdb
PDB 1o23 coloured by chain and viewed from the front.
PDB 1o23 coloured by chain and viewed from the side.
PDB 1o23 coloured by chain and viewed from the top.
Source organisms:
Primary publication:
alpha-Lactalbumin (LA) stimulates milk beta-1,4-galactosyltransferase I (beta 4Gal-T1) to transfer glucose from UDP-glucose to N-acetylglucosamine. Crystal structure of beta 4Gal-T1 x LA complex with UDP-Glc.
Ramakrishnan B, Shah PS, Qasba PK
J. Biol. Chem. 276 37665-71 (2001)
PMID: 11485999

Function and Biology Details

Reactions catalysed: 
UDP-alpha-D-galactose + N-acetyl-D-glucosamine = UDP + N-acetyllactosamine
UDP-alpha-D-galactose + D-glucose = UDP + lactose
UDP-alpha-D-galactose + N-acetyl-beta-D-glucosaminylglycopeptide = UDP + beta-D-galactosyl-(1->4)-N-acetyl-beta-D-glucosaminylglycopeptide
UDP-alpha-D-galactose + N-acetyl-beta-D-glucosaminyl-(1->3)-beta-D-galactosyl-(1->4)-beta-D-glucosyl-(1<->1)-ceramide = UDP + beta-D-galactosyl-(1->4)-N-acetyl-beta-D-glucosaminyl-(1->3)-beta-D-galactosyl-(1->4)-beta-D-glucosyl-(1<->1)-ceramide
Biochemical function:
Biological process:
Cellular component:
Sequence domains:
Structure domains:

Structure analysis Details

Assembly composition:
hetero dimer (preferred)
Entry contents:
2 distinct polypeptide molecules
Macromolecules (2 distinct):
Alpha-lactalbumin Chains: A, C
Molecule details ›
Chains: A, C
Length: 123 amino acids
Theoretical weight: 14.02 KDa
Source organism: Mus musculus
Expression system: Escherichia coli BL21
UniProt:
  • Canonical: P29752 (Residues: 21-143; Coverage: 100%)
Gene name: Lalba
Sequence domains: C-type lysozyme/alpha-lactalbumin family
Structure domains: Lysozyme
Beta-1,4-galactosyltransferase 1 Chains: B, D
Molecule details ›
Chains: B, D
Length: 286 amino acids
Theoretical weight: 32.85 KDa
Source organism: Bos taurus
Expression system: Escherichia coli BL21
UniProt:
  • Canonical: P08037 (Residues: 130-402; Coverage: 68%)
Gene names: B4GALT1, GALT, GGTB2
Sequence domains:
Structure domains: Spore Coat Polysaccharide Biosynthesis Protein SpsA; Chain A

Ligands and Environments

6 bound ligands:
Ligand CA 2 x CA
Ligand PG4 2 x PG4
Ligand MES 1 x MES
Ligand MN 2 x MN
Ligand UPG 2 x UPG
Ligand UDP 2 x UDP
No modified residues

Experiments and Validation Details

Entry percentile scores
X-ray source: NSLS BEAMLINE X9B
Spacegroup: P21
Unit cell:
a: 55.545Å b: 99.379Å c: 102.568Å
α: 90° β: 104.09° γ: 90°
R-values:
R R work R free
0.201 0.201 0.265
Expression system: Escherichia coli BL21

Quick links

Citations

13 review citations

Promiscuity and specificity of eukaryotic glycosyltransferases.
Biswas et al. (2020)
12 more

1 mention without citation

The N-acetyl-binding pocket of N-acetylglucosaminyltransferases also accommodates a sugar analog with a chemical handle at C2.
Pasek et al. (2012)