Structure of PDB 1i3n Chain B

Receptor sequence

>1i3nB (length=345) Species: 9606 (Homo sapiens)

AEKVLVTGGAGYIGSHTVLELLEAGYLPVVIDNFHNAFRGGGSLPESLRR
VQELTGRSVEFEEMDILDQGALQRLFKKYSFMAVIHFAGLKAMGESVQKP
LDYYRVNLTGTIQLLEIMKAHGVKNLVFSSSATVYGNPQYLPLDEAHPTG
GCTNPYGKSKFFIEEMIRDLCQADKTWNVVLLRYFNPTGAHASGCIGEDP
QGIPNNLMPYVSQVAIGRREALNVFGNDYDTEDGTGVRDYIHVVDLAKGH
IAALRKLKEQCGCRIYNLGTGTGYSVLQMVQAMEKASGKKIPYKVVARRE
GDVAACYANPSLAQEELGWTAALGLDRMCEDLWRWQKQNPSGFGT

3D structure

• PDB: 1i3n Molecular basis for severe epimerase deficiency galactosemia. X-ray structure of the human V94m-substituted UDP-galactose 4-epimerase.
• Chain: B
• Resolution: 1.5 Å

Enzymatic activity

• Catalytic site (original residue number in PDB): S132 A133 T134 Y157 K161
• Catalytic site (residue number reindexed from 1): S131 A132 T133 Y156 K160
• Enzyme Commision number: 5.1.3.2: UDP-glucose 4-epimerase.
  5.1.3.7: UDP-N-acetylglucosamine 4-epimerase.

Interaction with ligand

Site #	Ligand	Ligand chain	Binding residues on receptor (original residue number in PDB)	Binding residues on receptor (residue number reindexed from 1)	Binding affinity
BS01	NAD	B	G9 G12 Y13 I14 D33 N34 N37 D66 I67 F88 A89 G90 K92 S130 S131 Y157 K161 Y185 P188	G8 G11 Y12 I13 D32 N33 N36 D65 I66 F87 A88 G89 K91 S129 S130 Y156 K160 Y184 P187
BS02	UD1	B	N187 N206 N207 L208 N224 F226 R239 Y241 V277 R300 D303	N186 N205 N206 L207 N223 F225 R238 Y240 V276 R299 D302

Gene Ontology

Molecular Function

• GO:0003974 UDP-N-acetylglucosamine 4-epimerase activity
• GO:0003978 UDP-glucose 4-epimerase activity
• GO:0016853 isomerase activity
• GO:0042802 identical protein binding
• GO:0042803 protein homodimerization activity

Biological Process

• GO:0006012 galactose metabolic process
• GO:0019388 galactose catabolic process
• GO:0033499 galactose catabolic process via UDP-galactose

Cellular Component

• GO:0005829 cytosol

External links

• PDB: RCSB:1i3n, PDBe:1i3n, PDBj:1i3n
• PDBsum: 1i3n
• PubMed: 11279193
• UniProt: Q14376|GALE_HUMAN UDP-glucose 4-epimerase (Gene Name=GALE)