The bacterial flagellar switch complex is getting more complex

Cohen-Ben-Lulu, Galit N; Francis, Noreen R.; Shimoni, Eyal; Noy, Dror; Davidov, Yaacov; Prasad, K. Nagendra; Sagi, Yoav; Cecchini, Gary; Johnstone, Rose M.; Eisenbach, Michael

doi:10.1038/emboj.2008.48

Cited by 48 publications

(55 citation statements)

References 52 publications

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“…E. coli strain RP-2 (⌬sdhCDAB, ⌬frdABCD) lacks all subunits of SQR or QFR. Its construction was previously described, where its previous designation was RP437⌬sdh⌬frd (21). To construct the triple deletion strain RP-3 (⌬sdh⌬frd-⌬sdhE), P1 transduction of RP-2 was done following a standard protocol as previously described (21).…”

Section: Methodsmentioning

confidence: 99%

“…Its construction was previously described, where its previous designation was RP437⌬sdh⌬frd (21). To construct the triple deletion strain RP-3 (⌬sdh⌬frd-⌬sdhE), P1 transduction of RP-2 was done following a standard protocol as previously described (21). Briefly, the insertion of the kanamycin resistance gene in the position corresponding to sdhE in the ygfY-ygfX operon was verified by PCR amplification using a forward primer complement to a sequence of the beginning of kanamycin resistance gene (TAT GTC CTG ATA GCG GTC CGC C) and a reverse primer complement to the last 21 base pairs of the ygfX gene (TTA TCT TTG CGT CTC TTG TTG).…”

Section: Methodsmentioning

confidence: 99%

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Binding of the Covalent Flavin Assembly Factor to the Flavoprotein Subunit of Complex II

Maklashina

Rajagukguk

Starbird³

et al. 2016

Journal of Biological Chemistry

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Escherichia coli harbors two highly conserved homologs of the essential mitochondrial respiratory complex II (succinate: ubiquinone oxidoreductase). Aerobically the bacterium synthesizes succinate:quinone reductase as part of its respiratory chain, whereas under microaerophilic conditions, the quinol: fumarate reductase can be utilized. All complex II enzymes harbor a covalently bound FAD co-factor that is essential for their ability to oxidize succinate. In eukaryotes and many bacteria, assembly of the covalent flavin linkage is facilitated by a small protein assembly factor, termed SdhE in E. coli. How SdhE assists with formation of the covalent flavin bond and how it binds the flavoprotein subunit of complex II remain unknown. Using photo-cross-linking, we report the interaction site between the flavoprotein of complex II and the SdhE assembly factor. These data indicate that SdhE binds to the flavoprotein between two independently folded domains and that this binding mode likely influences the interdomain orientation. In so doing, SdhE likely orients amino acid residues near the dicarboxylate and FAD binding site, which facilitates formation of the covalent flavin linkage. These studies identify how the conserved SdhE assembly factor and its homologs participate in complex II maturation.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Binding of the Covalent Flavin Assembly Factor to the Flavoprotein Subunit of Complex II

Maklashina

Rajagukguk

Starbird³

et al. 2016

Journal of Biological Chemistry

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“…Hence, the tumble bias, which is determined by the CheY-p level, also differs from cell to cell. Furthermore, cells vary in total number and spatial distribution of receptors [55] and motors [56]. All this variability might be helpful under unpredictable changes of the environment, where having different phenotypes increases the chances of a species' survival [57].…”

Section: Cell-to-cell Variability and Cell Behaviormentioning

confidence: 99%

Bacterial chemotaxis: information processing, thermodynamics, and behavior

Micali

Endres

2016

Current Opinion in Microbiology

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Escherichia coli has long been used as a model organism due to the extensive experimental characterization of its pathways and molecular components. Take chemotaxis as an example, which allows bacteria to sense and swim in response to chemicals, such as nutrients and toxins. Many of the pathway's remarkable sensing and signaling properties are now concisely summarized in terms of design (or engineering) principles. More recently, new approaches from information theory and stochastic thermodynamics have begun to address how pathways process environmental stimuli and what the limiting factors are. However, to fully capitalize on these theoretical advances, a closer connection with single-cell experiments will be required. IntroductionAll living organisms from animals to unicellular bacteria live under constant evolutionary pressure. To stay ahead in the game of evolution, organisms need to process noisy information, allowing them to make survival decisions quickly. However, to process information and move organisms also require energy. Thus the final behavior of any organism has to be an outcome which produces strong advantages under likely occurring environments. Chemotaxis of Escherichia coli is particularly well understood in terms of its molecular components, allowing this bacterium to migrate towards food and away from toxins [1][2][3][4][5]. Indeed, an ever increasing amount of studies has highlighted several design principles, i.e. engineering blue prints, ensuring exquisite sensitivity, efficiency, robustness, and wide dynamic range at all levels of the pathway.This review focuses on recent findings in E. coli chemotaxis, in particular on how molecular mechanisms give rise to information processing, its associated thermodynamic cost, and the resulting swimming behavior. What new design principles will be discovered next? Classical view of Escherichia coli chemotaxisEscherichia coli is a Gram-negative bacterium inhabiting soil, as well as the animal and human gastrointestinal tracts. Inside the host, it contributes to the digestion of food and enhances resistance against pathogens [6]. This bacterium has a relatively simple chemotactic pathway (Fig. 1 1A). External stimuli are processed at the receptor level, where receptors sense and memorize chemical concentrations from the past by their adapted methylation level (Fig. 1A, see red box for 'sensing module'). The receptor-signaling activity can be monitored experimentally by tagging the CheY and CheZ proteins with a fluorescence-resonance-energy-transfer (FRET) reporter pair to follow their phosphorylation-dependent interaction. To swim cells are equipped with 5-8 flagellar rotary motors (Fig. 1A, blue box for 'motility module'), each of which rotates either clockwise (CW) or counterclockwise (CCW). Taking together these flagella determine cell movement, given either by a 'run' or a random reorientation in a 'tumble' [7][8][9]. The phosphorylated protein CheY-p links sensing and motility (Fig. 1A). In absence of any chemical gradient E. coli per...

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“…FliM also binds CheY-P via sequences in the first 16 amino acids, and elsewhere (15), to play a key role in switching flagellar rotation direction. FliG, the switch protein closest to the cytoplasmic membrane, interacts with the stator protein MotA, the FliF membrane protein that forms the flagellar basal-body MS ring, and the membrane-bound respiratory protein fumarate reductase (11). FliG has the most direct role in creating flagellar rotation.…”

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confidence: 99%

Functional Analysis of theHelicobacter pyloriFlagellar Switch Proteins

et al. 2009

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Helicobacter pylori uses flagellum-mediated chemotaxis to promote infection. Bacterial flagella change rotational direction by changing the state of the flagellar motor via a subcomplex referred to as the switch. Intriguingly, the H. pylori genome encodes four switch complex proteins, FliM, FliN, FliY, and FliG, instead of the more typical three of Escherichia coli or Bacillus subtilis. Our goal was to examine whether and how all four switch proteins participate in flagellation. Previous work determined that FliG was required for flagellation, and we extend those findings to show that all four switch proteins are necessary for normal numbers of flagellated cells. Furthermore, while fliY and fliN are partially redundant with each other, both are needed for wild-type levels of flagellation. We also report the isolation of an H. pylori strain containing an R54C substitution in fliM, resulting in bacteria that swim constantly and do not change direction. Along with data demonstrating that CheY-phosphate interacts with FliM, these findings suggest that FliM functions in H. pylori much as it does in other organisms.

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The bacterial flagellar switch complex is getting more complex

Cited by 48 publications

References 52 publications

Binding of the Covalent Flavin Assembly Factor to the Flavoprotein Subunit of Complex II

Binding of the Covalent Flavin Assembly Factor to the Flavoprotein Subunit of Complex II

Bacterial chemotaxis: information processing, thermodynamics, and behavior

Functional Analysis of theHelicobacter pyloriFlagellar Switch Proteins

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