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B6db activities: 2.6.1.89

2.6.1.89
Description dTDP-3-dehydro-6-deoxy-D-glucose aminotransferase
Alternative names dTDP-3-dehydro-6-deoxy-D-glucose 3-aminotransferase;
dTDP-3-keto-6-deoxy-D-glucose 3-aminotransferase;
TDP-3-dehydro-6-deoxy-D-glucose 3-aminotransferase;
TDP-3-keto-6-deoxy-D-glucose 3-aminotransferase.
QdtB
Catalyzed reaction dTDP-3-amino-3,6-dideoxy-alpha-D-glucopyranose + 2-oxoglutarate <=> dTDP-3-dehydro-6-deoxy-alpha-D-glucopyranose + L-glutamate
Cofactor Pyridoxal-phosphate.
Comments The reaction occurs in the reverse direction. The enzyme is involved in biosynthesis of D-mycaminose.
The enzyme plays a key role in the biosynthesis of 3-acetamido-3,6-dideoxy-α-D-glucose (Quip3NAc), a carbohydrate that is found in the cell-wall lipopolysaccharide antigens of some Gram-negative bacteria.

In Streptomyces fradiae, the same enzyme (there termed TylB) is involved in the biosynthesis of tylosin (a macrolide antibiotic). In this pathway, the product of the TylB reaction (TDP-3-amino-3,6-dideoxy-D-glucose) is subsequently dimethylated to form TDP-d-Mycaminose.

PDB 3FRK;
Organisms -Eubacteria
 

Family 

2.6.1.89 (0)
 
Links Enzyme (activities) 2.6.1.89
BRENDA (activities) 2.6.1.89
KEGG (pathways) 2.6.1.89
PLPMDB (PLP mutants) 2.6.1.89
 
References
 Thoden JB, Schäffer C, Messner P, Holden HM. (2009) Structural Analysis of QdtB, an Aminotransferase Required for the Biosynthesis of dTDP-3-acetamido-3,6-dideoxy-alpha-d-glucose Biochemistry 48 1553–1561.

 Pföstl A, Zayni S, Hofinger A, Kosma P, Schäffer C, Messner P. (2008) Biosynthesis of dTDP-3-acetamido-3,6-dideoxy-alpha-D-glucose Biochem J 410 187-94.

 Melançon CE 3rd, Hong L, White JA, Liu YN, Liu HW. (2007) Characterization of TDP-4-keto-6-deoxy-D-glucose-3,4-ketoisomerase from the D-mycaminose biosynthetic pathway of Streptomyces fradiae: in vitro activity and substrate specificity studies Biochemistry 46 577-90.

Articles on 2.6.1.89
 
last changed 2014/08/19 13:42

B6db activities