Role of rpoS in the regulation of glyoxalase III in Escherichia coli.

Abstract

Methylglyoxal is an endogenous electrophile produced in Escherichia coli by the enzyme methylglyoxal synthase to limit the accumulation of phosphorylated sugars. In enteric bacteria methylglyoxal is detoxified by the glutathione-dependent glyoxalase I/II system, by glyoxalase III, and by aldehyde reductase and alcohol dehydrogenase. Here we demonstrate that glyoxalase III is a stationary-phase enzyme. Its activity reached a maximum at the entry into the stationary phase and remained high for at least 20 h. An rpoS mutant displayed normal glyoxalase I and II activities but was unable to induce glyoxalase III in stationary phase. It thus appears that glyoxalase III is regulated by rpoS and might be important for survival of non-growing E. coli cultures.

Hsp31 of Escherichia coli K‐12 is glyoxalase III

“…Thus, the glyoxalase III may play a critical role in conditions with limiting carbon source. Previous studies indicate that the activity of glyoxalase I/II is constitutive irrespective of growth phases, while the glyoxalase III activity is variable, reaching a maximum in the stationary phase (Benov et al, 2004). Unlike glyoxalase I/II, the expression of glyoxalase III was not affected upon changes in major nutrients of growth medium (Misra et al, 1995).…”

“…The measurements of each glyoxalase activity revealed that the glyoxalase III was the most abundant enzyme in E. coli (Okado-Matsumoto and Fridovich, 2000). The reason for variability in glyoxalase III activity may be because the glyoxalase III is a stationary-phase enzyme, and its activity is regulated by rpoS (Benov et al, 2004). Thus, it is likely that Hsp31 plays an important role in protecting stationary-phase cells against carbonyl toxicity.…”

“…The expression of glyoxalase III was dependent on the growth phase, i.e. higher at the stationary phase because of its dependence on rpoS (Benov et al, 2004). Although the glyoxalase III plays a certain role in the degradation of MG, the corresponding gene has not been reported.…”

“…A single enzyme, designated glyoxalase III, catalysing the GSH-independent conversion of MG into D-lactate has been reported in Escherichia coli (Misra et al, 1995;MacLean et al, 1998;Okado-Matsumoto and Fridovich, 2000;Benov et al, 2004). This enzyme was inactivated by thiol-blocking reagents and reactivated by thiol-containing agents, indicating the involvement of the thiol group for catalysis (Misra et al, 1995).…”

The glyoxalase pathway: the first hundred years… and beyond

“…However, this is not a very efficient enzyme with a k cat /K m value of 1.8 × 10 3 M − 1 •s − 1 [110], when compared with GLO1, which has a k cat /K m value of 1.2 × 10 7 M − 1 •s − 1 [111]. GLO3 increases its expression during the bacterial stationary growth phase and is regulated by rpoS (RNA polymerase sigma factor) [112]. This enzyme exhibits a higher activity than GLO1 and GLO2 and represents the main system for methylglyoxal The metal co-ordination site and the molecular surface silhouette around the substrate-binding site are shown for the human (PDB code 1QH5) (A) and L. infantum (PDB code 2P18) (B) enzymes.…”