PMID- 12775214
OWN - NLM
STAT- MEDLINE
DCOM- 20030930
LR  - 20181113
IS  - 1470-8728 (Electronic)
IS  - 0264-6021 (Print)
IS  - 0264-6021 (Linking)
VI  - 374
IP  - Pt 3
DP  - 2003 Sep 15
TI  - Overexpression of UDP-glucose dehydrogenase in Escherichia coli results in 
      decreased biosynthesis of K5 polysaccharide.
PG  - 767-72
AB  - The Escherichia coli K5 capsular polysaccharide (glycosaminoglycan) chains are 
      composed of the repeated disaccharide structure: 
      -GlcAbeta1,4-GlcNAcalpha1,4-(where GlcA is glucuronic acid and GlcNAc is 
      N-acetyl-D-glucosamine). The GlcA, present in most glycosaminoglycans, is donated 
      from UDP-GlcA, which, in turn, is generated from UDP-glucose by the enzyme 
      UDP-glucose dehydrogenase (UDPGDH). The formation of UDP-GlcA is critical for the 
      biosynthesis of glycosaminoglycans. To investigate the role of UDPGDH in 
      glycosaminoglycan biosynthesis, we used K5 polysaccharide biosynthesis as a 
      model. E. coli was transformed with the complete gene cluster for K5 
      polysaccharide production. Additional transformation with an extra copy of UDPGDH 
      resulted in an approx. 15-fold increase in the in vitro UDPGDH enzyme activity 
      compared with the strain lacking extra UDPGDH. UDP-GlcA levels were increased 
      3-fold in overexpressing strains. However, metabolic labelling with [14C]glucose 
      showed, unexpectedly, that overexpression of UDPGDH lead to decreased formation 
      of K5 polysaccharide. No significant difference in the K5 polysaccharide chain 
      length was observed between control and overexpressing strains, indicating that 
      the decrease in K5-polysaccharide production most probably was due to synthesis 
      of fewer chains. Our results suggest that K5-polysaccharide biosynthesis is 
      strictly regulated such that increasing the amount of available UDP-GlcA results 
      in diminished K5-polysaccharide production.
FAU - Roman, Elisabet
AU  - Roman E
AD  - Department of Medical Biochemistry and Microbiology, University of Uppsala, BMC 
      Box 582, SE-751 23 Uppsala, Sweden.
FAU - Roberts, Ian
AU  - Roberts I
FAU - Lidholt, Kerstin
AU  - Lidholt K
FAU - Kusche-Gullberg, Marion
AU  - Kusche-Gullberg M
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Biochem J
JT  - The Biochemical journal
JID - 2984726R
RN  - 0 (Escherichia coli Proteins)
RN  - 0 (Polysaccharides, Bacterial)
RN  - 2616-64-0 (Uridine Diphosphate Glucuronic Acid)
RN  - 42615-44-1 (capsular polysaccharide K5)
RN  - EC 1.1.1.22 (KfiD protein, E coli)
RN  - EC 1.1.1.22 (Uridine Diphosphate Glucose Dehydrogenase)
SB  - IM
MH  - Bacterial Capsules/biosynthesis/genetics
MH  - Depression, Chemical
MH  - Escherichia coli Proteins/*biosynthesis/genetics
MH  - Genetic Vectors
MH  - Polysaccharides, Bacterial/*biosynthesis/chemistry
MH  - Transfection
MH  - Uridine Diphosphate Glucose Dehydrogenase/*biosynthesis/genetics
MH  - Uridine Diphosphate Glucuronic Acid/chemistry
PMC - PMC1223629
EDAT- 2003/05/31 05:00
MHDA- 2003/10/01 05:00
PMCR- 2004/03/15
CRDT- 2003/05/31 05:00
PHST- 2003/05/30 00:00 [accepted]
PHST- 2003/05/20 00:00 [revised]
PHST- 2003/03/07 00:00 [received]
PHST- 2003/05/31 05:00 [pubmed]
PHST- 2003/10/01 05:00 [medline]
PHST- 2003/05/31 05:00 [entrez]
PHST- 2004/03/15 00:00 [pmc-release]
AID - BJ20030365 [pii]
AID - 10.1042/BJ20030365 [doi]
PST - ppublish
SO  - Biochem J. 2003 Sep 15;374(Pt 3):767-72. doi: 10.1042/BJ20030365.