Identification and characterization of the tolQRA genes of Pseudomonas aeruginosa

Dennis, Jonathan J.; Lafontaine, Eric R.; Sokol, Pamela A.

doi:10.1128/jb.178.24.7059-7068.1996

Cited by 54 publications

(65 citation statements)

References 53 publications

(55 reference statements)

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“…Indeed, tolQRAB pal mutations have been extensively characterized in many Gram-negative bacteria (Dennis et al, 1996;Fortney et al, 2000;Heilpern & Waldor, 2000;Llamas et al, 2000;Prouty et al, 2002). Mutants in all these genes are impaired in the so-called phenotype of outer-membrane integrity: release of periplasmic content in the extracellular medium, increased sensitivity to deleterious agents such as bile salts, motility and outer-membrane blebbing (P. putida), and entry of filamentous phage DNA (E. coli, V. cholerae).…”

Section: Discussionmentioning

confidence: 99%

“…Attempts to construct tol-pal mutants in some bacteria have been unsuccessful, and could be explained by their poor growth in classical rich media, as observed for Er. chrysanthemi tol-pal mutants (Dennis et al, 1996;Spinola et al, 1996).…”

Section: Discussionmentioning

confidence: 99%

“…In E. coli, group A colicins and filamentous-phage DNA use the Tol proteins for their translocation across the cell envelope (Bouveret et al, 1998;Webster, 1991). The existence of tolpal genes has now been established in several Gram-negative bacteria (Bowe et al, 1998;Dennis et al, 1996;Heilpern & Waldor, 2000;Llamas et al, 2000;Prouty et al, 2002;Youderian et al, 2003). There is also evidence that some of the tol-pal genes are involved in the pathogenesis of E. coli (Hellman et al, 2002), Haemophilus ducreyi (Fortney et al, 2000), Salmonella enterica (Bowe et al, 1998) and Vibrio cholerae (Heilpern & Waldor, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Tol-Pal proteins are critical cell envelope components of Erwinia chrysanthemi affecting cell morphology and virulence

Dubuisson

Vianney

Hugouvieux‐Cotte‐Pattat

et al. 2005

Microbiology

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The tol-pal genes are necessary for maintaining the outer-membrane integrity of Gram-negative bacteria. These genes were first described in Escherichia coli, and more recently in several other species. They are involved in the pathogenesis of E. coli, Haemophilus ducreyi, Vibrio cholerae and Salmonella enterica. The role of the tol-pal genes in bacterial pathogenesis was investigated in the phytopathogenic enterobacterium Erwinia chrysanthemi, assuming that this organism might be a good model for such a study. The whole Er. chrysanthemi tol-pal region was characterized. Tol-Pal proteins, except TolA, showed high identity scores with their E. coli homologues. Er. chrysanthemi mutants were constructed by introducing a uidA-kan cassette in the ybgC, tolQ, tolA, tolB, pal and ybgF genes. All the mutants were hypersensitive to bile salts. Mutations in tolQ, tolA, tolB and pal were deleterious for the bacteria, which required high concentrations of sugars or osmoprotectants for their viability. Consistent with this observation, they were greatly impaired in their cell morphology and division, which was evidenced by observations of cell filaments, spherical forms, membrane blebbing and mislocalized bacterial septa. Moreover, tol-pal mutants showed a reduced virulence in a potato tuber model and on chicory leaves. This could be explained by a combination of impaired phenotypes in the tol-pal mutants, such as reduced growth and motility and a decreased production of pectate lyases, the major virulence factor of Er. chrysanthemi. INTRODUCTIONThe Tol-Pal system of Gram-negative bacteria is required for outer-membrane stability (Lazzaroni et al., 1999). It comprises five envelope proteins, TolQ, TolR, TolA, TolB and Pal, which form two complexes. The TolQ, TolR and TolA inner-membrane proteins interact via their transmembrane domains (Derouiche et al., 1995;Lazzaroni et al., 1995). The b-propeller domain of the periplasmic protein TolB is responsible for its interaction with Pal (Ray et al., 2000). TolB also interacts with the outer-membrane peptidoglycan-associated proteins Lpp and OmpA (Cascales et al., 2002;Clavel et al., 1998). TolA undergoes a conformational change in response to changes in the protonmotive force (Germon et al., 2001), and interacts with Pal in an energy-dependent manner (Cascales et al., 2001). The Cterminal periplasmic domain of TolA also interacts with the N-terminal domain of TolB (Dubuisson et al., 2002;Walburger et al., 2002).The transcriptional organization of the E. coli tol-pal genes has been characterized. The genes ybgC (orf1), tolQ, tolR, tolA and tolB, and pal and ybgF (orf2) form two operons (Muller & Webster, 1997); a large ybgC-ybgF transcript has also been postulated (Vianney et al., 1996). ybgC and ybgF encode proteins of unknown function located in the cytoplasm and the periplasm, respectively (Clavel et al., 1996;Sun & Webster, 1987). Inactivation of these two ORFs induces no obvious phenotype in E. coli. In contrast, mutations in the tol-pal genes cause the disruption of outermembr...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Tol-Pal proteins are critical cell envelope components of Erwinia chrysanthemi affecting cell morphology and virulence

Dubuisson

Vianney

Hugouvieux‐Cotte‐Pattat

et al. 2005

Microbiology

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“…Pyocins S1, S2, and S3 probably belong to TonB-dependent bacteriocins because their highest activity is detected on susceptible cells grown under iron-limited conditions and because of their use of the ferripyoverdine receptor FpvA as a receptor (19,136,169,494,572,602). In contrast, pyocin AP41 is more related to Tol-dependent colicins because it is inactive on Pseudomonas aeruginosa tolQRA cells (146,273,372). Chimeras between S-type pyocins and colicins have been constructed and indicate that both receptor binding and translocation domains are species specific (316,318,572).…”

Section: Pyocinsmentioning

confidence: 99%

“…It involves a complex network of interactions, which have been defined and characterized by a combination of biochemical, structural, and genetic approaches (391,413). Its physiological role is unclear, but the tol-pal genes have been shown to be essential in pathogens such as Pseudomonas aeruginosa, Haemophilus ducreyi, and enteropathogenic Escherichia coli O157 (146,214,611). Mutations within the Escherichia coli K-12 tol genes were identified in the late 1960s by their insensitivity to colicins (474,475,487).…”

Section: Tol-dependent Colicinsmentioning

confidence: 99%

Colicin Biology

Cascales

Buchanan

Duché

et al. 2007

Microbiol Mol Biol Rev

970

1,324

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SUMMARY Colicins are proteins produced by and toxic for some strains of Escherichia coli. They are produced by strains of E. coli carrying a colicinogenic plasmid that bears the genetic determinants for colicin synthesis, immunity, and release. Insights gained into each fundamental aspect of their biology are presented: their synthesis, which is under SOS regulation; their release into the extracellular medium, which involves the colicin lysis protein; and their uptake mechanisms and modes of action. Colicins are organized into three domains, each one involved in a different step of the process of killing sensitive bacteria. The structures of some colicins are known at the atomic level and are discussed. Colicins exert their lethal action by first binding to specific receptors, which are outer membrane proteins used for the entry of specific nutrients. They are then translocated through the outer membrane and transit through the periplasm by either the Tol or the TonB system. The components of each system are known, and their implication in the functioning of the system is described. Colicins then reach their lethal target and act either by forming a voltage-dependent channel into the inner membrane or by using their endonuclease activity on DNA, rRNA, or tRNA. The mechanisms of inhibition by specific and cognate immunity proteins are presented. Finally, the use of colicins as laboratory or biotechnological tools and their mode of evolution are discussed.

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Circular dichroism and molecular modeling of theE. coli TolA periplasmic domains

Derouiche¹,

Lloubès²,

Sasso³

et al. 1999

Biospectroscopy

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Colicins are killer proteins that use envelope proteins from the outer and the inner membranes to reach their cellular target in susceptible cells of Escherichia coli. Each group A colicin uses a combination of Tol proteins to cross the outer membrane of gram‐negative bacteria and to exert their killing activity. The TolA protein, necessary for the import of all the group A colicins, is a 421‐amino acid residue protein composed of three domains (TolAI, TolAII, and TolAIII). TolAIII interacts with the N‐terminal domain of colicin A (AT1). Analytical ultracentrifugation reveals that TolAII and TolAIII are monomer structures, TolAII has an elongated structure, and TolAIII is rather globular. Circular dichroism (CD) spectra were done with TolAII‐III, TolAII, TolAIII, AT1, and the AT1–TolAII‐III complex. TolA CD spectra reveal the presence of α‐helix structure in aqueous solution and the intensity of the α‐helix signal is the highest with TolAII. Few structural changes are observed with the complex AT1–TolAII‐III. Molecular modeling was done for TolAII‐III, taking into account CD and ultracentrifugation data and show that domain II can adopt a barrel structure made of three twisted α‐helices similar to coiled coil helices while domain III can adopt a globular structure. © 1999 John Wiley & Sons, Inc. Biospectroscopy 5: 189–198, 1999

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Identification and characterization of the tolQRA genes of Pseudomonas aeruginosa

Cited by 54 publications

References 53 publications

Tol-Pal proteins are critical cell envelope components of Erwinia chrysanthemi affecting cell morphology and virulence

Tol-Pal proteins are critical cell envelope components of Erwinia chrysanthemi affecting cell morphology and virulence

Colicin Biology

Circular dichroism and molecular modeling of theE. coli TolA periplasmic domains

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