The <i>Escherichia coli</i> phage‐shock‐protein (<i>psp</i>) operon

Model, Peter; Jovanović, Goran; Dworkin, Jonathan

doi:10.1046/j.1365-2958.1997.3481712.x

Cited by 185 publications

(132 citation statements)

References 40 publications

(79 reference statements)

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“…The predicted mass of the PspA protein was 25?5 kDa. Synthesis of PspA protein in E. coli has been reported to correlate with membrane stress in this bacterium (Model et al, 1997). The identity of the 26 kDa protein was confirmed in vivo to be PspA by expressing the cobS gene from plasmid pCOBS4 in strain BL21(DE3) Dpsp : : kan + and comparing the protein pattern to that of strain BL21(DE3) psp + /pCOBS4 (Fig.…”

Section: Expression Of the Cobs Gene In E Colimentioning

confidence: 92%

“…Functions encoded by the psp operon play a role in responding to changes in the energy level of the cell. PspA, an inner-membrane protein, is believed to prevent the loss of protons across the inner membrane, maintaining the proton-motive force (Brissette et al, 1990;Kleerebezem et al, 1996;Model et al, 1997). The implications of a membrane-associated synthesis of coenzyme B 12 are discussed.…”

Section: Introductionmentioning

confidence: 99%

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The last step in coenzyme B12 synthesis is localized to the cell membrane in bacteria and archaea

2004

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In Salmonella enterica, the last step of the synthesis of adenosylcobamide is catalysed by the cobalamin synthase enzyme encoded by the cobS gene of this bacterium. Overexpression of the S. enterica cobS gene in Escherichia coli elicited the accumulation of the phage shock protein PspA, a protein whose expression has been linked to membrane stress. Resolution of inner and outer membranes of S. enterica by isopycnic density ultracentrifugation showed CobS activity associated with the inner membrane, a result that was confirmed using antibodies against CobS. Computer analysis of the predicted amino acid sequence of CobS suggested it was an integral membrane protein.Results of experiments performed with strains carrying plasmids encoding CobS-alkaline phosphatase or CobS-b-galactosidase protein fusions were consistent with the membrane localization of the CobS protein. Modifications to the predicted model were made based on data obtained from experiments using protein fusions. The function encoded by the cobS orthologue in the methanogenic archaeon Methanobacterium thermoautotrophicum strain DH compensated for the lack of CobS during cobalamin synthesis in cobS strains of S. enterica. Cobalamin synthase activity was also detected in a membrane preparation of M. thermoautotrophicum. It was concluded that the assembly of the nucleotide loop of adenosylcobamides in archaea and bacteria is a membrane-associated process. Possible reasons for the association of adenosylcobamide biosynthetic enzymes with the cell membrane are discussed.

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Section: Expression Of the Cobs Gene In E Colimentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

The last step in coenzyme B12 synthesis is localized to the cell membrane in bacteria and archaea

2004

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“…(22) Therefore productive interactions between the EBP and s 54 are conditioned by the state of the nucleotide bound to the activator, seemingly by the sensing of the g-phosphate of ATP. (9) The recent study by Bordes et al (1) determined that a unique sequence present within s 54 -dependent EBPs is involved in directly binding s 54 and that this sequence is not static, but subject to movement in a nucleotide-dependent fashion.…”

Section: Overviewmentioning

confidence: 99%

“…In order to better understand the intimate interactions made between the EBP and s 54 -RNAP, Bordes and colleagues (1) conducted protein fragmentation studies with the E. coli EBP phage shock protein F (PspF), a transcription regulator involved in stress response. (21,22) The fragmentation approach was adopted to overcome the problem of overlapping functionality associated with full-length protein-the activities of the full-length protein are interlinked. Therefore the fragmentation approach can be used to isolate or uncouple individual functions within specific sequence motifs.…”

Section: Introductionmentioning

confidence: 99%

Investigating protein–protein interfaces in bacterial transcription complexes: a fragmentation approach

Burrows

2003

BioEssays

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SummaryTranscription initiation by s 54 -RNA polymerase (RNAP) relies explicitly on a transient interaction with a complex molecular machine belonging to the AAAþ (ATPases associated with various cellular activities) superfamily. Members of the AAAþ superfamily convert chemical energy derived from NTP hydrolysis to a mechanical force used to remodel their target substrate. Recently Bordes and colleagues, (1) using a protein fragmentation approach, identified a unique sequence within s 54 -dependent transcriptional activators that constitutes a s 54 -binding interface. This interface is not static, but subject to nucleotide-dependent movement which may represent a common mechanism for controlling output that has been adopted by other AAAþ proteins. IntroductionDefining the types of strategy and the mechanisms used to control gene expression is important for a full understanding of how the genetic information stored within DNA can be unlocked. Elaborate signal pathways exist to ensure that genes are only expressed when required, thus enabling flexible adaptation in response to changing environmental conditions. At the heart of these pathways lie transcription factors, which regulate the activity of DNA-dependent RNA polymerase (RNAP), the central enzyme in gene expression. Bacterial RNAP is a multisubunit enzyme with subunit composition a 2 bb 0 o; In this 'core' form, the RNAP is catalytically competent but incapable of locating specific DNA target sequences,

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“…It is under the control of the s 54 -RNAP subunit (the rpoN gene product). The first s 54 -dependent heat shock operon, pspA-E, was described by Model's group (Brissette et al, 1991;Model et al, 1997). Later, it was found that the ibpB gene is transcribed not only from the s 32 promoter upstream of the ibpAB operon (Allen et al, 1992), but also from the internal s 54 promoter situated in the ibpA-ibpB intergenic space (Kuczyń ska-Wiśnik et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

A σ 54-dependent promoter in the regulatory region of the Escherichia coli rpoH gene

et al. 2007

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The Escherichia coli rpoH gene is transcribed from four known and differently regulated promoters: P1, P3, P4 and P5. This study demonstrates that the conserved consensus sequence of the s 54 promoter in the regulatory region of the rpoH gene, described previously, is a functional promoter, P6. The evidence for this conclusion is: (i) the specific binding of the s 54 -RNAP holoenzyme to P6, (ii) the location of the transcription start site at the predicted position (C, 30 nt upstream of ATG) and (iii) the dependence of transcription on s 54 and on an ATP-dependent activator. Nitrogen starvation, heat shock, ethanol and CCCP treatment did not activate transcription from P6 under the conditions examined. Two activators of s 54 promoters, PspF and NtrC, were tested but neither of them acted specifically. Therefore, PspFDHTH, a derivative of PspF, devoid of DNA binding capability but retaining its ATPase activity, was used for transcription in vitro, taking advantage of the relaxed specificity of ATP-dependent activators acting in solution. In experiments in vivo overexpression of PspFDHTH from a plasmid was employed. Thus, the s 54 -dependent transcription capability of the P6 promoter was demonstrated both in vivo and in vitro, although the specific conditions inducing initiation of the transcription remain to be elucidated. The results clearly indicate that the closed s 54 -RNAP-promoter initiation complex was formed in vitro and in vivo and needed only an ATP-dependent activator to start transcription.

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The Escherichia coli phage‐shock‐protein (psp) operon

Cited by 185 publications

References 40 publications

The last step in coenzyme B12 synthesis is localized to the cell membrane in bacteria and archaea

The last step in coenzyme B12 synthesis is localized to the cell membrane in bacteria and archaea

Investigating protein–protein interfaces in bacterial transcription complexes: a fragmentation approach

A σ 54-dependent promoter in the regulatory region of the Escherichia coli rpoH gene

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