Genetic and biochemical characterization of an operon involved in the biosynthesis of 3-deoxy-D-manno-octulosonic acid in Pseudomonas aeruginosa.
A Pseudomonas aeruginosa serotype O5 (PAO1) genomic DNA fragment that was able to complement a temperature-sensitive mutation in the 3-deoxy-D-manno-octulosonic acid (Kdo) 8-P synthase gene (kdsA) of Salmonella enterica serovar typhimurium was cloned. Nucleotide sequence analysis revealed the presence of a potential operon with the gene order pyrG, kdsA, eno. PyrG catalyzes the synthesis of the nucleotide cytidine triphosphate, while Eno catalyzes the formation of phosphoenolpyruvate from phosphoglycerate during glycolysis. Phosphoenolpyruvate is one of the substrates for Kdo-8-P biosynthesis by KdsA and cytidine triphosphate is the nucleotide used to activate Kdo prior to its transfer to lipid A. pyrG and eno are important for many metabolic pathways and it is interesting to find them linked to kdsA. A sigma 70-like promoter was found upstream of pyrG and evidence was provided to show that this promoter was responsible for the initiation of transcription of the genes in this operon. These genes mapped to 28.2-29.9 min on the 75-min PAO1 chromosome, unlinked to other lipopolysaccharide biosynthetic gene clusters.
Walsh
A G
AG
Canadian Bacterial Diseases Network, Department of Microbiology, University of Guelph, Ont., Canada.
Burrows
L L
LL
Lam
J S
JS
D000446:Aldehyde-Lyases / Q000235:genetics* / Q000378:metabolism; D019731:Carbon-Nitrogen Ligases / Q000235:genetics* / Q000378:metabolism; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D012321:DNA-Directed RNA Polymerases; D004926:Escherichia coli / Q000235:genetics; D005816:Genetic Complementation Test; D009876:Operon / Q000235:genetics*; D010751:Phosphopyruvate Hydratase / Q000235:genetics* / Q000378:metabolism; D020161:Physical Chromosome Mapping; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa / Q000201:enzymology / Q000235:genetics*; D012486:Salmonella typhimurium / Q000235:genetics; D012808:Sigma Factor; D013400:Sugar Acids / Q000378:metabolism*
D012808:Sigma Factor; D013400:Sugar Acids; C002532:2-keto-3-deoxyoctonate; C020011:2-dehydro-3-deoxyphosphooctonate aldolase; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; D000446:Aldehyde-Lyases; D010751:Phosphopyruvate Hydratase; D019731:Carbon-Nitrogen Ligases; C019951:CTP synthetase