› 4l41

X-ray diffraction
2.7Å resolution

Human Lactose synthase: A 2:1 complex between human alpha-lactalbumin and human beta1,4-galactosyltransferase

Released:
DOI: 10.2210/pdb4l41/pdb
PDB entry 4l41 coloured by chain, front view.
PDB entry 4l41 coloured by chain, side view.
PDB entry 4l41 coloured by chain, top view.
Source organism: Homo sapiens
Entry authors: Ramakrishnan B, Qasba PK

Function and Biology Details

Reactions catalysed: 
UDP-alpha-D-galactose + D-glucose = UDP + lactose
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
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-D-glucosamine = UDP + N-acetyllactosamine
Biochemical function:
Biological process:
Cellular component:
  • not assigned
Sequence domains:

Structure analysis Details

Assembly composition:
hetero trimer (preferred)
Assembly name:
PDBe Complex ID:
PDB-CPX-132932 (preferred)
Entry contents:
2 distinct polypeptide molecules
Macromolecules (2 distinct):
Alpha-lactalbumin Chains: A, B
Molecule details ›
Chains: A, B
Length: 124 amino acids
Theoretical weight: 14.16 KDa
Source organism: Homo sapiens
Expression system: Escherichia coli BL21
UniProt:
  • Canonical: P00709 (Residues: 19-142; Coverage: 100%)
Gene names: LALBA, LYZL7
Sequence domains: C-type lysozyme/alpha-lactalbumin family
Structure domains: Lysozyme
Processed beta-1,4-galactosyltransferase 1 Chain: C
Molecule details ›
Chain: C
Length: 287 amino acids
Theoretical weight: 32.77 KDa
Source organism: Homo sapiens
Expression system: Escherichia coli BL21
UniProt:
  • Canonical: P15291 (Residues: 126-398; Coverage: 69%)
Gene names: B4GALT1, GGTB2
Sequence domains:
Structure domains: Spore Coat Polysaccharide Biosynthesis Protein SpsA; Chain A

Ligands and Environments

2 bound ligands:
Ligand CA 2 x CA
Ligand SO4 1 x SO4
No modified residues

Experiments and Validation Details

Entry percentile scores
X-ray source: NSLS BEAMLINE X9B
Spacegroup: P21
Unit cell:
a: 62.39Å b: 65.21Å c: 71.72Å
α: 90° β: 114.45° γ: 90°
R-values:
R R work R free
0.19 0.188 0.237
Expression system: Escherichia coli BL21

Quick links