CATH Classification

Domain Context

CATH Clusters

Superfamily Type I PLP-dependent aspartate aminotransferase-like (Major domain)
Functional Family

Enzyme Information

4.2.1.168
GDP-4-dehydro-6-deoxy-alpha-D-mannose 3-dehydratase.
based on mapping to UniProt Q9F118
GDP-4-dehydro-alpha-D-rhamnose + L-glutamate = GDP-4-dehydro-3,6-dideoxy- alpha-D-mannose + 2-oxoglutarate + ammonia.
-!- This enzyme, involved in beta-L-colitose biosynthesis, is a unique vitamin-B6-dependent enzyme. -!- In the first step of catalysis, the bound pyridoxal phosphate (PLP) cafactor is transaminated to the pyridoxamine 5'-phosphate (PMP) form of vitamin B(6), using L-glutamate as the amino group donor. -!- The PMP cofactor then forms a Schiff base with the sugar substrate and the resulting adduct undergoes a 1,4-dehydration to eliminate the 3-OH group. -!- Hydrolysis of the product from the enzyme restores the PLP cofactor and results in the release of an unstable enamine intermediate. -!- This intermediate tautomerizes to form an imine form, which hydrolyzes spontaneously, releasing ammonia and forming the final product.

UniProtKB Entries (1)

Q9F118
Q9F118_ECOLX
Escherichia coli
DegT/DnrJ/EryC1/StrS family aminotransferase

PDB Structure

PDB 2GMS
External Links
Method X-RAY DIFFRACTION
Organism Escherichia
Primary Citation
The structure of GDP-4-keto-6-deoxy-D-mannose-3-dehydratase: a unique coenzyme B6-dependent enzyme.
Cook, P.D., Thoden, J.B., Holden, H.M.
Protein Sci.