Metabolism‐dependent taxis towards (methyl)phenols is coupled through the most abundant of three polar localized Aer‐like proteins of <i>Pseudomonas putida</i>

Sarand, Inga; Osterberg, S; Holmqvist, Sofie; Holmfeldt, Per; Skärfstad, Eleonore; Parales, Rebecca E.; Shingler, Victoria

doi:10.1111/j.1462-2920.2007.01546.x

Cited by 59 publications

(88 citation statements)

References 48 publications

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“…Given the ecological advantage provided by energy taxis (24), energy taxis transducers are expected to be widespread in bacteria; however, only a few have been identified thus far (7,8,10,14,15). Here we characterize an energy taxis chemoreceptor, AerC, in the nitrogen-fixing bacterium, A. brasilense.…”

Section: Discussionmentioning

confidence: 99%

“…In contrast to the best studied PAS-domain containing chemoreceptor, Aer of E. coli, and similar chemoreceptors characterized in other bacteria (14,15), AerC is a soluble protein. The PAS domain of Aer contains FAD (16,17); however, PAS domains are ubiquitous and contain various other cofactors (11).…”

Section: Identification Of Aerc a Cytoplasmic Chemoreceptor With Elementioning

confidence: 99%

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PAS domain containing chemoreceptor couples dynamic changes in metabolism with chemotaxis

Xie¹,

Ulrich

Zhulin

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

107

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Chemoreceptors provide sensory specificity and sensitivity that enable motile bacteria to seek optimal positions for growth and metabolism in gradients of various physicochemical cues. Despite the abundance of chemoreceptors, little is known regarding the sensory specificity and the exact contribution of individual chemoreceptors to the lifestyle of bacteria. Azospirillum brasilense are motile bacteria that can fix atmospheric nitrogen under microaerophilic conditions. Here, we characterized a chemoreceptor in this organism, named AerC, which functions as a redox sensor that enables the cells to seek microaerophilic conditions that support optimum nitrogen fixation. AerC is a representative of a widespread class of soluble chemoreceptors that monitor changes in the redox status of the electron transport system via the FAD cofactor associated with its PAS domains. In A. brasilense, AerC clusters at the cell poles. Its cellular localization and contribution to the behavioral response correlate with its expression pattern and with changes in the overall cellular FAD content under nitrogenfixing conditions. AerC-mediated energy taxis in A. brasilense prevails under conditions of nitrogen fixation, illustrating a strategy by which cells optimize chemosensing to signaling cues that directly affect current metabolic activities and thus revealing a mechanism by which chemotaxis is coordinated with dynamic changes in cell physiology.FAD | nitrogen fixation | signal transduction M otile bacteria detect changes in environmental conditions and respond by navigating toward niches where conditions are optimal for growth. This widespread behavior is collectively known as chemotaxis (1). Various physicochemical cues are detected by dedicated chemoreceptors (methyl-accepted chemotaxis proteins or MCPs) that relay information to the flagellar motors via a signal transduction cascade (2). The model organism for chemotaxis, Escherichia coli, possesses five transmembrane chemoreceptors (Tar, Tsr, Tap, Trg, and Aer) and the sensory specificities for each of these have been determined (2). Most bacterial species have a greater number of chemoreceptors than E. coli (3); however, their sensory specificities and contribution to the lifestyle of bacteria are virtually unknown.Azospirillum brasilense are motile bacteria that can fix atmospheric nitrogen under microaerophilic conditions. These bacteria respond tactically to various chemoeffectors that affect their metabolism and the resulting changes in energy levels function as signals (4). In oxygen gradients, A. brasilense cells quickly navigate to a specific zone where oxygen concentration is low enough (3-5 μM) to support their microaerobic lifestyle and to be compatible with nitrogen fixation (5). Chemotactic responses to changes in energy metabolism have been identified in several bacterial species and are collectively referred to as "energy taxis" (6). In E. coli, two of the five chemoreceptors have been implicated in mediating energy taxis: Aer, which senses the redox status via an...

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Section: Discussionmentioning

confidence: 99%

Section: Identification Of Aerc a Cytoplasmic Chemoreceptor With Elementioning

confidence: 99%

PAS domain containing chemoreceptor couples dynamic changes in metabolism with chemotaxis

Xie¹,

Ulrich

Zhulin

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

107

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“…The promoter region of P. putida dksA was then amplified as a KpnI to SacI fragment using primers dksApro-f and dksApro-r and inserted between these sites of pKm705L to generate pVI906 for subsequent single site recombination into the chromosome of P. putida as previously described (22).…”

mentioning

confidence: 99%

“…To generate a monocopy luxAB transcriptional reporter of the dksA promoter in P. putida, we used the Km R R6K-based suicide plasmid pKm705L that carries the promoterless luxAB genes downstream of a polylinker (22). The promoter region of P. putida dksA was then amplified as a KpnI to SacI fragment using primers dksApro-f and dksApro-r and inserted between these sites of pKm705L to generate pVI906 for subsequent single site recombination into the chromosome of P. putida as previously described (22).…”

mentioning

confidence: 99%

σ54-Promoter Discrimination and Regulation by ppGpp and DksA

Bernardo¹,

Johansson²,

Skärfstad

et al. 2009

Journal of Biological Chemistry

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The 54 -factor controls expression of a variety of genes in response to environmental cues. Much previous work has implicated the nucleotide alarmone ppGpp and its co-factor DksA in control of 54 -dependent transcription in the gut commensal Escherichia coli, which has evolved to live under very different environmental conditions than Pseudomonas putida. Here we compared ppGpp/DksA mediated control of 54 -dependent transcription in these two organisms. Our in vivo experiments employed P. putida mutants and manipulations of factors implicated in ppGpp/DksA mediated control of 54 -dependent transcription in combination with a series of 54 -promoters with graded affinities for 54 -RNA polymerase. For in vitro analysis we used a P. putida-based reconstituted 54 -transcription assay system in conjunction with DNA-binding plasmon resonance analysis of native and heterologous 54 -RNA polymerase holoenzymes. In comparison with E. coli, ppGpp/DksA responsive 54 -transcription in the environmentally adaptable P. putida was found to be more robust under low energy conditions that occur upon nutrient depletion. The mechanism behind this difference can be traced to reduced promoter discrimination of low affinity 54 -promoters that is conferred by the strong DNA binding properties of the P. putida 54 -RNA polymerase holoenzyme.To ensure promoter specificity, the bacterial multisubunit catalytic core RNA polymerase (RNAP) 4 (␣ 2 ␤␤Ј) is guided to the distinct promoter classes within the genome by a dissociable -factor. In addition to the household 70 -factor, most bacteria encode a variable number of alternative -factors that fall into two families based on primary amino acid sequences and regulatory properties. The largest of these is the 70 -family, which encompasses most alternative -factors within four subgroups that all form RNAP holoenzymes that can spontaneously initiate transcription (1). Orthologs of the structurally distinct 54 -subunit are the only members of the second family. 54 imposes kinetic constrains that lock the 54 -RNAP holoenzyme in a non-productive closed complex. Thus, 54 -dependent transcription always requires activators, called bacterial enhancer-binding proteins or bEBPs, which use ATP catalysis to remodel 54

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“…Responses to (methyl)phenols and phenylacetic acid are mediated through energy taxis via Aer2 (Luu et al, 2013;Sarand et al, 2008), whilst responses to naphthalene, 2-nitrobenzoate, toluene, 4-chloroaniline, catechol and aromatic amino acids are sensed by chemotaxis via specific MCPs (Grimm & Harwood, 1999;Iwaki et al, 2007;Lacal et al, 2011;Oku et al, 2012;Parales et al, 2000;Taguchi et al, 1997;Vangnai et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

Cytosine chemoreceptor McpC in Pseudomonas putida F1 also detects nicotinic acid

et al. 2014

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Soil bacteria are generally capable of growth on a wide range of organic chemicals, and pseudomonads are particularly adept at utilizing aromatic compounds. Pseudomonads are motile bacteria that are capable of sensing a wide range of chemicals, using both energy taxis and chemotaxis. Whilst the identification of specific chemicals detected by the ¢26 chemoreceptors encoded in Pseudomonas genomes is ongoing, the functions of only a limited number of Pseudomonas chemoreceptors have been revealed to date. We report here that McpC, a methyl-accepting chemotaxis protein in Pseudomonas putida F1 that was previously shown to function as a receptor for cytosine, was also responsible for the chemotactic response to the carboxylated pyridine nicotinic acid.

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Metabolism‐dependent taxis towards (methyl)phenols is coupled through the most abundant of three polar localized Aer‐like proteins of Pseudomonas putida

Cited by 59 publications

References 48 publications

PAS domain containing chemoreceptor couples dynamic changes in metabolism with chemotaxis

PAS domain containing chemoreceptor couples dynamic changes in metabolism with chemotaxis

σ54-Promoter Discrimination and Regulation by ppGpp and DksA

Cytosine chemoreceptor McpC in Pseudomonas putida F1 also detects nicotinic acid

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