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The phage-shock-protein (Psp) system responds to extracytoplasmic stress that may reduce the energy status of the cell. It is conserved in many different bacteria and has been linked to several important phenotypes. Escherichia coli psp mutants have defects in maintenance of the proton-motive force, protein export by the sec and tat pathways, survival in(More)
The phage shock protein locus (pspFpspABCDE) of Escherichia coli has proved to be something of an enigma since its discovery. The physiological functions of the psp locus, including those of the predicted effector protein PspA, are unknown. In a previous genetic screen, we determined that a Yersinia enterocolitica pspC mutant was severely attenuated for(More)
The expression of several Escherichia coli operons is activated by the Fnr protein during anaerobic growth and is further controlled in response to nitrate and nitrite by the homologous response regulators, NarL and NarP. Among these operons, the napF operon, encoding a periplasmic nitrate reductase, has unique features with respect to its Fnr-, NarL-, and(More)
The phage-shock-protein (Psp) system is essential for Yersinia enterocolitica virulence. Mislocalized secretins induce psp gene expression, and kill psp null strains. We used transposon mutagenesis to investigate whether other genes are required to tolerate secretin-induced stress. Our motivation included the possibility of identifying signal transducers(More)
The NarL and NarP proteins are homologous response regulators of Escherichia coli that control the expression of several operons in response to nitrate and nitrite. A consensus heptameric NarL DNA-binding sequence has been identified, and previous observations suggest that the NarP protein has a similar sequence specificity. However, some operons are(More)
Pathogenic Yersinia species are associated with both localized and systemic infections in mammalian hosts. In this study, signature-tagged transposon mutagenesis was used to identify Yersinia enterocolitica genes required for survival in a mouse model of infection. Approximately 2000 transposon insertion mutants were screened for attenuation. This led to(More)
PspA, -B and -C regulate the bacterial phage shock protein stress response by controlling the PspF transcription factor. Here, we have developed complementary approaches to study the behaviour of these proteins at their endogenous levels in Yersinia enterocolitica. First, we observed GFP-tagged versions with an approach that resolves individual protein(More)
Regulation of the bacterial phage-shock-protein (Psp) system involves communication between integral (PspBC) and peripheral (PspA) cytoplasmic membrane proteins and a soluble transcriptional activator (PspF). In this study protein subcellular localization studies were used to distinguish between spatial models for this putative signal transduction pathway(More)
Secretins are bacterial outer membrane proteins that are important for protein export. However, they can also mislocalize and cause stress to the bacterial cell, which is dealt with by the well-conserved phage shock protein (Psp) system in a highly specific manner. Nevertheless, some bacteria have secretins but no Psp system. A notable example is(More)
During anaerobic growth, expression of the fdnGHI and narGHJI operons of Escherichia coli is induced by the NarL protein in response to nitrate. The fdnG operon control region contains four NarL-binding sites (termed NarL heptamers) between positions -70 and -130. The two central NarL heptamers of fdnG are arranged as an inverted repeat and are essential(More)