The Pseudomonas aeruginosa devB/SOL Homolog pgl Is a Member of the hex Regulon and Encodes 6-Phosphogluconolactonase

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

M. Worth Calfee (Creator)

Paul W. Hager (Creator)

Paul V. Phibbs (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: A cyclic version of the Entner-Doudoroff pathway is used by Pseudomonas aeruginosa to metabolize carbohydrates. Genes encoding the enzymes that catabolize intracellular glucose to pyruvate and glyceraldehyde 3- phosphate are coordinately regulated clustered at 39 min on the chromosome and collectively form the hex regulon. Within the hex cluster is an open reading frame (ORF) with homology to the devB/SOL family of unidentified proteins. This ORF encodes a protein of either 243 or 238 amino acids; it overlaps the 5* end of zwf (encodes glucose-6-phosphate dehydrogenase) and is followed immediately by eda (encodes the Entner-Doudoroff aldolase). The devB/SOL homolog was inactivated in P. aeruginosa PAO1 by recombination with a suicide plasmid containing an interrupted copy of the gene creating mutant strain PAO8029. PAO8029 grows at 9% of the wild-type rate using mannitol as the carbon source and at 50% of the wild-type rate using gluconate as the carbon source. Cell extracts of PAO8029 were specifically deficient in 6-phosphogluconolactonase (Pgl) activity. The cloned devB/SOL homolog complemented PAO8029 to restore normal growth on mannitol and gluconate and restored Pgl activity. Hence we have identified this gene as pgl and propose that the devB/SOL family members encode 6-phosphogluconolactonases. Interestingly three eukaryotic glucose-6-phosphate dehydrogenase (G6PDH) isozymes from human rabbit and Plasmodium falciparum contain Pgl domains suggesting that the sequential reactions of G6PDH and Pgl are incorporated in a single protein. 6-Phosphogluconolactonase activity is induced in P. aeruginosa PAO1 by growth on mannitol and repressed by growth on succinate and it is expressed constitutively in P. aeruginosa PAO8026 (hexR). Taken together these results establish that Pgl is an essential enzyme of the cyclic Entner-Doudoroff pathway encoded by pgl a structural gene of the hex regulon. Originally published in Journal of Bacteriology July 2000 Vol. 182 No. 14

Additional Information

Publication

Other

Journal of Bacteriology. 182:14(July 2000) p. 3934-3941.

Language: English

Date: 2011

Keywords

Pseudomonas aeruginosa, carbohydrate metabolism, hex regulon, gene regulation, devB/SOL

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