Escherichia coliORFybhEispglgene encoding 6-phosphogluconolactonase (EC 3.1.1.31) that has no homology with known 6PGLs from other organisms

Abstract

The pentose-phosphate pathway (PPP) is an important part of central metabolism in many organisms. A pgl(-) mutation that decreases the efficiency of the second stage of PPP has been described and mapped at approx. 17.2 min of the Escherichia coli chromosome more than 30 years ago. Although it has recently been shown that deletion of ORF ybhE leads to earlier detected Pgl(-) phenotype for E. coli mutant strain, 6-phosphogluconolactonase from this organism has not been characterized. In the present, independent investigation we show that the Pgl(-) phenotype of DeltaybhE MG1655 could be complemented by insertion of the well-characterized pgl gene from Pseudomonas putida whose protein product has no visible homology with E. coli YbhE. Moreover, a final confirmation that ybhE actually encodes 6PGL in E. coli was obtained through overexpression of the cloned gene, purification of the protein product, followed by direct determination of its enzymatic activity in vitro.

The PA4204 gene encodes a periplasmic gluconolactonase (PpgL) which is important for fitness of Pseudomonas aeruginosa

“…PGLs have an important function in the oxidative branch of the pentose phosphate pathway, since they convert d-6-phosphogluconolactone, the product of the glucose 6-phosphate dehydrogenation, to 6-phosphogluconate, which can enter the Entner-Doudoroff (ED) pathway (Kupor & Fraenkel, 1969;Miclet et al, 2001;Thomason et al, 2004;Zimenkov et al, 2005). In the absence of PGL, d-6-phosphogluconolactone can spontaneously isomerize to c-6-phosphogluconolactone, which is toxic (Miclet et al, 2001;Zimenkov et al, 2005). Two kinds of 6-phosphogluconolactonases, which are not structurally similar, have been described: the Escherichia coli PGL type, and the Pseudomonas type (Hager et al, 2000).…”

“…Two kinds of 6-phosphogluconolactonases, which are not structurally similar, have been described: the Escherichia coli PGL type, and the Pseudomonas type (Hager et al, 2000). Interestingly, the PGL of Pseudomonas aeruginosa is a cytoplasmic enzyme encoded by another gene, PA3182, while PA4204 is similar to YbhE, the E. coli PGL (Thomason et al, 2004;Zimenkov et al, 2005). PGLs therefore have not only a catalytic function, but also prevent the accumulation of toxic, non-degradable metabolites, having an important 'house-cleaning' function (Galperin et al, 2006).…”

Enterococcus faecalis 6-Phosphogluconolactonase Is Required for Both Commensal and Pathogenic Interactions with Manduca sexta

“…Standard errors for all points were less than 1.7 M; thus, error bars have been omitted for clarity. (G) Schematic of 6-PGL enzyme activity assay (modeled after the pentose phosphate pathway diagram by Zimenkov et al [31]), with steps labeled 1 to 3 corresponding to the times of addition of the enzymes specified in panel F.…”

Extracellular Aldonolactonase from Myceliophthora thermophila

“…The equilibrium constant between glucono-␦-lactone and gluconic acid is 7.7, favoring gluconic acid, and the half-life of glucono-␦-lactone in water at room temperature and pH 5.0 is approximately 1 h (26). Despite this lack of stability, enzymes have evolved to catalyze the hydrolysis of sugar lactones.Enzymatic hydrolysis of sugar lactones has been studied most thoroughly in the context of the pentose phosphate pathway (8,13,28,34). In the pentose phosphate pathway, glucose-6-phosphate is converted to 6-phosphogluconolactone by glucose-6-phosphate dehydrogenase.…”

“…Enzymatic hydrolysis of sugar lactones has been studied most thoroughly in the context of the pentose phosphate pathway (8,13,28,34). In the pentose phosphate pathway, glucose-6-phosphate is converted to 6-phosphogluconolactone by glucose-6-phosphate dehydrogenase.…”