The ArgR Regulatory Protein, a Helper to the Anaerobic Regulator ANR during Transcriptional Activation of the arcD Promoter in Pseudomonas aeruginosa

Abstract

Pseudomonas aeruginosa, when deprived of oxygen, generates ATP from arginine catabolism by enzymes of the arginine deiminase pathway, encoded by the arcDABC operon. Under conditions of low oxygen tension, the transcriptional activator ANR binds to a site centered 41.5 bp upstream of the arcDtranscriptional start. ANR-mediated anaerobic induction was enhanced two- to threefold by extracellular arginine. This arginine effect depended, in trans, on the transcriptional regulator ArgR and, in cis, on an ArgR binding site centered at −73.5 bp in the arcD promoter. Binding of purified ArgR protein to this site was demonstrated by electrophoretic mobility shift assays and DNase I footprinting. This ArgR recognition site contained a sequence, 5′-TGACGC-3′, which deviated in only 1 base from the common sequence motif 5′-TGTCGC-3′ found in other ArgR binding sites of P. aeruginosa. Furthermore, an alignment of all known ArgR binding sites confirmed that they consist of two directly repeated half-sites. In the absence of ANR, arginine did not induce thearc operon, suggesting that ArgR alone does not activate the arcD promoter. According to a model proposed, ArgR makes physical contact with ANR and thereby facilitates initiation ofarc transcription.

Phylogeny of the bacterial superfamily of Crp-Fnr transcription regulators: exploiting the metabolic spectrum by controlling alternative gene programs

“…The pathway is expressed in P. aeruginosa under anaerobic conditions in the presence of the substrate. Anoxia is sensed by the Fnr-type regulator Anr [48], and the arginine signal is processed via the ArgR repressor [117]. Expression of the deiminase pathway in Bacillus licheniformis [118], Enterococcus faecalis [119], Lactobacillus sakei [120], and Oenococcus oeni [121] is dependent on ArcR regulators but, other than Anr of P. aeruginosa, these are not FeS proteins.…”

The CbrA–CbrB two‐component regulatory system controls the utilization of multiple carbon and nitrogen sources in Pseudomonas aeruginosa

“…We hypothesized that CbrB may activate the aot±argR operon, in concert with ArgR, to express the transport system and ArgR. As a consequence, the ArgR concentration would reach the level required for activation of the aru operon and for the regulation of other arginine-related genes (Park et al, 1997b;Lu et al, 1999;Ochs et al, 1999). In order to investigate this hypothesis, we measured b-galactosidase activities of aotJ 0 ± 0 lacZ and aruC 0 ± 0 lacZ fusions (Park et al, 1997b;Nishijyo et al, 1998) in the cbrA, cbrB and argR mutants.…”

“…The argR gene is the last member of the aot±argR operon, which also encodes an arginine and ornithine transport system (aotJQMP) and is located upstream of the aruCFGDB operon (Itoh, 1997;Nishijyo et al, 1998). ArgR activates the aot±argR and aru operons, as well as the oprD, gdhB and arcDBAC genes, in the presence of arginine (Itoh and Matsumoto, 1992;Itoh, 1997;Park et al, 1997b;Nishijyo et al, 1998;Lu et al, 1999;Ochs et al, 1999;Lu and Abdelal, 2001). Conversely, ArgR represses the anabolic argF and carAB genes when arginine is present in the medium (Itoh and Matsumoto, 1992;Park et al, 1997a).…”

“…Conversely, ArgR represses the anabolic argF and carAB genes when arginine is present in the medium (Itoh and Matsumoto, 1992;Park et al, 1997a). Such reciprocal regulation is a result of ArgR binding to the operator (ArgR box) in the relevant promoters (Park et al, 1997b;Nishijyo et al, 1998;Lu et al, 1999;Ochs et al, 1999). As ArgR does not require arginine for binding to the Arg box in vitro (Park et al, 1997b), the mechanism by which arginine controls these promoters remains unclear.…”

Two-pronged survival strategy for the major cystic fibrosis pathogen, Pseudomonas aeruginosa, lacking the capacity to degrade nitric oxide during anaerobic respiration

“…Loci involved in the four-step reduction of NO 3 À to N 2 are termed nar (nitrate reductase) (Sias et al, 1980), nir (nitrite reductase) (Silvestrini et al, 1989), nor (nitric oxide reductase) (Arai et al, 1995), and, finally, nos (nitrous oxide reductase) genes (Arai et al, 2003), respectively. Transcriptional control of genes involved in anaerobic respiration and arginine substrate level phosphorylation in PA is dependent upon ANR (anaerobic nitrate regulator), an FNR (fumarate/nitrate regulator/CRP)-like transactivator (Galimand et al, 1991;Lu et al, 1999). ANR is also required for transcription of the downstream regulator DNR (Arai et al, 1997).…”