All Three Endogenous Quinone Species of Escherichia coli Are Involved in Controlling the Activity of the Aerobic/Anaerobic Response Regulator ArcA

Abstract

The enteron Escherichia coli is equipped with a branched electron transfer chain that mediates chemiosmotic electron transfer, that drives ATP synthesis. The components of this electron transfer chain couple the oxidation of available electron donors from cellular metabolism (e.g., NADH, succinate, lactate, formate, etc.) to the reduction of electron acceptors like oxygen, nitrate, fumarate, di-methyl-sulfoxide, etc. Three different quinones, i.e., ubiquinone, demethyl-menaquinone and menaquinone, couple the transfer of electrons between the dehydrogenases and reductases/oxidases that constitute this electron transfer chain, whereas, the two-component regulation system ArcB/A regulates gene expression, to allow the organism to adapt itself to the ambient conditions of available electron donors and acceptors. Here, we report that E. coli can grow and adjust well to transitions in the availability of oxygen, with any of the three quinones as its single quinone. In all three ‘single-quinone’ E. coli strains transitions in the activity of ArcB are observed, as evidenced by changes in the level of phosphorylation of the response regulator ArcA, upon depletion/readmission of oxygen. These results lead us to conclude that all quinol species of E. coli can reduce (i.e., activate) the sensor ArcB and all three quinones oxidize (i.e., de-activate) it. These results also confirm our earlier conclusion that demethyl-menaquinone can function in aerobic respiration.

The Possible Roles of Escherichia coli in the Nitrogen Cycle

“…It is known that specific strains of E. coli do vary in having nitrate reductase which is most active under anaerobic conditions (Potter et al 1999). Similarly, authors have shown that anaerobic conditions may be important as triggers to nitrate reductase, hence nitrate utilization (Ishimoto and Yamamoto 1977;Noguchi et al 1997;Whitehead and Cole 2006;Warry et al 2008;van Beilen and Hellingwerf 2016). Again, the type of strain used may play a significant role as nitrate utilization is strain specific.…”

Allosteric regulation of menaquinone (vitamin K2) biosynthesis in the human pathogen Mycobacterium tuberculosis

“…MK levels are known to be tightly linked to the redox potential in bacteria (2,3,(7)(8)(9)(10); however, the molecular mechanisms that regulate this phenomenon are unclear. The first committed step in MK biosynthesis in Mtb is catalyzed by the thiamine diphosphate (ThDP)-dependent enzyme MenD (2-succinyl-5enolpyruvyl-6-hydroxy-3-cyclohexadiene-1-carboxylate synthase, SEPHCHC synthase).…”

Redox-Based Transcriptional Regulation in Prokaryotes: Revisiting Model Mechanisms

“…Recently, it has been reported that a third type of quinone (demethyl menaquinone) is involved in ArcB phosphorylation modulation. It seems that demethyl menaquinone is also able to oxydize ArcB and that demethyl menaquinol is able to reduce ArcB (376).…”