Rapid accumulation of intracellular 2-keto-3-deoxy-6-phosphogluconate in an Entner-Doudoroff aldolase mutant results in bacteriostasis

• Published in: FEMS microbiology letters 1998-02, Vol.159 (2), p.261-266
• Main Authors: Fuhrman, Lorra K, Wanken, Amy, Nickerson, Kenneth W, Conway, Tyrrell
• Format: Article
• Language: English
• Subjects: 2‐Keto‐3‐deoxy‐6‐phosphogluconate accumulation; Accumulation; Aldehyde-Lyases - physiology; Aldolase; Anion exchanging; Bacteriology; Bacteriostasis; Biological and medical sciences; Dehydration; E coli; Entner-Doudoroff pathway; Escherichia coli - physiology; Fundamental and applied biological sciences. Psychology; Gluconates - metabolism; High-performance liquid chromatography; Intracellular; Liquid chromatography; Metabolism. Enzymes; Microbiology; Mutation; Pentose; Pentose Phosphate Pathway; Phosphogluconate dehydratase; Phosphogluconate dehydrogenase (decarboxylating); Phosphogluconate Dehydrogenase - antagonists & inhibitors; Toxicity
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.1998.tb12870.x

Abstract The accumulation of 2-keto-3-deoxy-6-phosphogluconate, the key intermediate of the Entner-Doudoroff pathway, has long been thought to inhibit growth of bacteria, but careful measurements of 2-keto-3-deoxy-6-phosphogluconate accumulation by growing cells and the correlation of intracellular 2-keto-3-deoxy-6-phosphogluconate levels to growth inhibition had not been made. A system designed for this purposed was developed in Escherichia coli strains, allowing 2-keto-3-deoxy-6-phosphogluconate accumulation to be experimentally induced and measured by extraction of the cell pool. Addition of gluconate to a strain which lacked 2-keto-3-deoxy-6-phosphogluconate aldolase and overproduced 6-phosphogluconate dehydratase resulted in an increase in the intracellular concentration of 2-keto-3-deoxy-6-phosphogluconate from undetectable levels to 2.0 mM within 15 s, as measured by anion-exchange HPLC. The accumulation of 2-keto-3-deoxy-6-phosphogluconate was correlated with an immediate and significant decrease in growth; this inhibition was determined to be bacteriostatic and not bactericidal. It had been proposed that the mechanism of 2-keto-3-deoxy-6-phosphogluconate toxicity involves competitive inhibition of 6-phosphogluconate dehydrogenase and the consequent block of the pentose phosphate pathway. An experiment addressing this hypothesis failed to provide any supporting data.