scholarly journals Multiple Regulators Control Expression of the Entner-Doudoroff Aldolase (Eda) of Escherichia coli

2005 ◽  
Vol 187 (3) ◽  
pp. 991-1000 ◽  
Author(s):  
Elizabeth L. Murray ◽  
Tyrrell Conway
Keyword(s):  
Escherichia Coli ◽  
Phosphate Starvation ◽  
Growth Conditions ◽  
Carbon Starvation ◽  
Expression Level ◽  
Phosphate Limitation ◽  
Induced Stress ◽  
Indirect Mechanism ◽  
Complex Regulation

ABSTRACT The Escherichia coli eda gene, which encodes the Entner-Doudoroff aldolase, is central to the catabolism of several sugar acids. Here, we show that Eda synthesis is induced by growth on gluconate, glucuronate, or methyl-β-d-glucuronide; phosphate limitation; and carbon starvation. Transcription of eda initiates from three promoters, designated P1, P2, and P4, each of which is responsible for induction under different growth conditions. P1 controls eda induction on gluconate and is regulated by GntR. P2 controls eda induction on glucuronate and galacturonate and is regulated by KdgR. P4 is active under conditions of phosphate starvation and is directly controlled by PhoB. In addition, CsrA activates Eda synthesis, apparently by an indirect mechanism that may be involved in the modest changes in expression level that are associated with carbon starvation. The complex regulation of eda is discussed with respect to its several physiological roles, which apparently accommodate not only sugar acid catabolism but also detoxification of metabolites that could accumulate during starvation-induced stress.

3-D structure analysis of PhoE porin

1986 ◽  
Vol 44 ◽  
pp. 164-165
Author(s):  
Bing K. Jap
Keyword(s):  
Escherichia Coli ◽  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Phosphate Starvation ◽  
Growth Conditions ◽  
Free Diffusion ◽  
Similar Molecular Weight ◽  
Phoe Porin ◽  
Pore Forming Proteins

The outer membrane of Escherichia coli contains a variety of pore-forming proteins called porins. These proteins have similar molecular weight and amino acid composition, but have substantially different chemical specificities for restricting free diffusion of aqueous solutes. One porin, called PhoE, is preferentially expressed under growth conditions involving phosphate starvation. PhoE porin serves not only as a nonspecific channel for small solutes, but also facilitates the diffusion of phosphate containing solutes as well as other negatively charged compounds.

scholarly journals Transcription of ppk from Acinetobacter sp. Strain ADP1, Encoding a Putative Polyphosphate Kinase, Is Induced by Phosphate Starvation

1998 ◽  
Vol 64 (3) ◽  
pp. 896-901 ◽  
Author(s):  
Walter Geißdörfer ◽  
Andreas Ratajczak ◽  
Wolfgang Hillen
Keyword(s):  
Escherichia Coli ◽  
Phosphate Starvation ◽  
Single Copy ◽  
Phosphate Concentration ◽  
Phosphate Limitation ◽  
Polyphosphate Kinase ◽  
Constitutive Promoter ◽  
Galactosidase Activity ◽  
E Coli ◽  
Extension Analysis

ABSTRACT Polyphosphate kinase (Ppk) catalyzes the formation of polyphosphate from ATP. We cloned the ppk gene (2,073 bp) fromAcinetobacter sp. strain ADP1; this gene encodes a putative polypeptide of 78.6 kDa with extensive homology to polyphosphate kinase from Escherichia coli and other bacteria. Chromosomal disruption of ppk by inserting a transcriptionally fusedlacZ does not affect growth under conditions of phosphate limitation or excess. β-Galactosidase activity expressed from the single-copy ppk::lacZ fusion is induced 5- to 15-fold by phosphate starvation. An increased amount ofppk transcript (2.2 kb) was detected when cells were grown at a limiting phosphate concentration. Primer extension analysis revealed a regulated promoter located upstream of a second, constitutive promoter. Potential similarities of this regulation with the effects of PhoB and PhoR of E. coli are discussed.

Physiologische Bedeutung der „Stringent Control“ bei Escherichia coli unter extremen Hungerbedingungen / Stringent Control and Starvation Survival in Escherichia coli

1989 ◽  
Vol 44 (9-10) ◽  
pp. 838-844 ◽  
Author(s):  
H. Mach ◽  
M. Hecker ◽  
I. Hill ◽  
A. Schroeter ◽  
F. Mach
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Amino Acid ◽  
Protein Turnover ◽  
Stringent Response ◽  
Phosphate Starvation ◽  
Pleiotropic Effects ◽  
Prolonged Starvation ◽  
Stringent Control ◽  
Starvation Survival

The viability of three isogenic relA+/relA strain pairs of Escherichia coli (CP78/CP79; NF 161/ NF162; CP 107/CP 143) was studied during prolonged starvation for amino acids, glucose or phosphate. After amino acid limitation we found a prolonged viability of all relA+ strains which synthesized ppGpp. We suggest that some ppGpp-mediated pleiotropic effects of the stringent response (e.g. glykogen accumulation, enhanced protein turnover) might be involved in this prolongation of survival. After glucose or phosphate starvation there was no difference in the relA+/relA strains either in the ppGpp content or in the survival.

scholarly journals A Rhodobacter sphaeroides Protein Mechanistically Similar to Escherichia coli DksA Regulates Photosynthetic Growth

mBio ◽  
2014 ◽  
Vol 5 (3) ◽  
Author(s):  
Christopher W. Lennon ◽  
Kimberly C. Lemmer ◽  
Jessica L. Irons ◽  
Max I. Sellman ◽  
Timothy J. Donohue ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Structure Function ◽  
Rhodobacter Sphaeroides ◽  
Fatty Acid Content ◽  
Regulatory Protein ◽  
Growth Conditions ◽  
Globular Domain ◽  
Content Type ◽  
E Coli

ABSTRACTDksA is a global regulatory protein that, together with the alarmone ppGpp, is required for the “stringent response” to nutrient starvation in the gammaproteobacteriumEscherichia coliand for more moderate shifts between growth conditions. DksA modulates the expression of hundreds of genes, directly or indirectly. Mutants lacking a DksA homolog exhibit pleiotropic phenotypes in other gammaproteobacteria as well. Here we analyzed the DksA homolog RSP2654 in the more distantly relatedRhodobacter sphaeroides, an alphaproteobacterium. RSP2654 is 42% identical and similar in length toE. coliDksA but lacks the Zn finger motif of theE. coliDksA globular domain. Deletion of the RSP2654 gene results in defects in photosynthetic growth, impaired utilization of amino acids, and an increase in fatty acid content. RSP2654 complements the growth and regulatory defects of anE. colistrain lacking thedksAgene and modulates transcriptionin vitrowithE. coliRNA polymerase (RNAP) similarly toE. coliDksA. RSP2654 reduces RNAP-promoter complex stabilityin vitrowith RNAPs fromE. coliorR. sphaeroides, alone and synergistically with ppGpp, suggesting that even though it has limited sequence identity toE. coliDksA (DksAEc), it functions in a mechanistically similar manner. We therefore designate the RSP2654 protein DksARsp. Our work suggests that DksARsphas distinct and important physiological roles in alphaproteobacteria and will be useful for understanding structure-function relationships in DksA and the mechanism of synergy between DksA and ppGpp.IMPORTANCEThe role of DksA has been analyzed primarily in the gammaproteobacteria, in which it is best understood for its role in control of the synthesis of the translation apparatus and amino acid biosynthesis. Our work suggests that DksA plays distinct and important physiological roles in alphaproteobacteria, including the control of photosynthesis inRhodobacter sphaeroides. The study of DksARsp, should be useful for understanding structure-function relationships in the protein, including those that play a role in the little-understood synergy between DksA and ppGpp.

Reduction of a Kinetic Model of the Carbon Starvation Response in Escherichia coli

2009 ◽  
Vol 42 (10) ◽  
pp. 27-32
Author(s):  
Delphine Ropers ◽  
Valentina Baldazzi ◽  
Hidde de Jong
Keyword(s):  
Escherichia Coli ◽  
Kinetic Model ◽  
Carbon Starvation ◽  
Starvation Response

scholarly journals Characterization of the Two Mycobacterium tuberculosis recA Promoters

2003 ◽  
Vol 185 (20) ◽  
pp. 6005-6015 ◽  
Author(s):  
Krishna K. Gopaul ◽  
Patricia C. Brooks ◽  
Jean-François Prost ◽  
Elaine O. Davis
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Mycobacterium Tuberculosis ◽  
Promoter Activity ◽  
The Other ◽  
Expression Level ◽  
Promoter Elements ◽  
Kinetics Of

ABSTRACT The recA gene of Mycobacterium tuberculosis is unusual in that it is expressed from two promoters, one of which, P1, is DNA damage inducible independently of LexA and RecA, while the other, P2, is regulated by LexA in the classical way (E. O. Davis, B. Springer, K. K. Gopaul, K. G. Papavinasasundaram, P. Sander, and E. C. Böttger, Mol. Microbiol. 46:791-800, 2002). In this study we characterized these two promoters in more detail. Firstly, we localized the promoter elements for each of the promoters, and in so doing we identified a mutation in each promoter which eliminates promoter activity. Interestingly, a motif with similarity to Escherichia coli σ70 −35 elements but located much closer to the −10 element is important for optimal expression of P1, whereas the sequence at the −35 location is not. Secondly, we found that the sequences flanking the promoters can have a profound effect on the expression level directed by each of the promoters. Finally, we examined the contribution of each of the promoters to recA expression and compared their kinetics of induction following DNA damage.

scholarly journals The Escherichia coli cysG promoter belongs to the ‘extended −10’ class of bacterial promoters

1993 ◽  
Vol 296 (3) ◽  
pp. 851-857 ◽  
Author(s):  
T Belyaeva ◽  
L Griffiths ◽  
S Minchin ◽  
J Cole ◽  
S Busby
Keyword(s):  
Escherichia Coli ◽  
Point Mutations ◽  
Growth Conditions ◽  
Upstream Region ◽  
E Coli ◽  
Run Off ◽  
A Site ◽  
Specific Sequences

The Escherichia coli cysG promoter has been subcloned and shown to function constitutively in a range of different growth conditions. Point mutations identify the -10 hexamer and an important 5′-TGN-3′ motif immediately upstream. The effects of different deletions suggest that specific sequences in the -35 region are not essential for the activity of this promoter in vivo. This conclusion was confirmed by in vitro run-off transcription assays. The DNAase I footprint of RNA polymerase at the cysG promoter reveals extended protection upstream of the transcript start, and studies with potassium permanganate as a probe suggest that the upstream region is distorted in open complexes. Taken together, the results show that the cysG promoter belongs to the ‘extended -10’ class of promoters, and the base sequence is similar to that of the P1 promoter of the E. coli galactose operon, another promoter in this class. In vivo, messenger initiated at the cysG promoter appears to be processed by cleavage at a site 41 bases downstream from the transcript start point.

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