scholarly journals The N-Acetyltransferase RimJ Responds to Environmental Stimuli To Repress pap Fimbrial Transcription in Escherichia coli

2002 ◽  
Vol 184 (16) ◽  
pp. 4334-4342 ◽  
Author(s):  
Christine A. White-Ziegler ◽  
Alia M. Black ◽  
Stacie H. Eliades ◽  
Sarah Young ◽  
Kimberly Porter
Keyword(s):  
Escherichia Coli ◽  
Low Temperature ◽  
Synthetic Lethality ◽  
Phase Variation ◽  
Luria Bertani ◽  
Thermoregulatory Response ◽  
Gene Encoding ◽  
Environmental Stimuli ◽  
Variation Mechanism ◽  
Insertion Mutations

ABSTRACT In uropathogenic Escherichia coli, P pili (Pap) facilitate binding to host epithelial cells and subsequent colonization. Whereas P pili can be produced at 37°C, the expression of these fimbriae is suppressed at 23°C. Previously, insertion mutations in rimJ, a gene encoding the N-terminal acetyltransferase of ribosomal protein S5, were shown to disrupt this thermoregulatory response, allowing papBA transcription at low temperature. In this study, we created an in-frame deletion of rimJ. This deletion relieved the repressive effects not only of low temperature but also of rich (Luria-Bertani [LB]) medium and glucose on papBA transcription, indicating that RimJ modulates papBA transcription in response to multiple environmental stimuli. papI transcription was also shown to be regulated by RimJ. papBA transcription is also controlled by a phase variation mechanism. We demonstrated that the regulators necessary to establish a phase ON state—PapI, PapB, Dam, Lrp, and cyclic AMP-CAP-are still required for papBA transcription in a rimJ mutant strain. rimJ mutations increase the rate at which bacteria transition into the phase ON state, indicating that RimJ inhibits the phase OFF→ON transition. A ΔrimJ hns651 mutant is viable on LB medium but not on minimal medium. This synthetic lethality, along with transcriptional analyses, indicates that RimJ and H-NS work through separate pathways to control papBA transcription. Mutations in rimJ do not greatly influence the transcription of the fan, daa, or fim operon, suggesting that RimJ may be a pap-specific regulator. Overexpression of rimJ under conditions repressive for papBA transcription complements the ΔrimJ mutation but has little effect on transcription under activating conditions, indicating that the ability of RimJ to regulate transcription is environmentally controlled.

scholarly journals Translational Regulation of the Escherichia coli Stress Factor RpoS: a Role for SsrA and Lon

2007 ◽  
Vol 189 (13) ◽  
pp. 4872-4879 ◽  
Author(s):  
Caroline Ranquet ◽  
Susan Gottesman
Keyword(s):  
Escherichia Coli ◽  
Low Temperature ◽  
Rna Polymerase ◽  
Transcription Initiation ◽  
Translational Regulation ◽  
Regulatory Rna ◽  
Gene Encoding ◽  
Ribosome Stalling ◽  
High Level ◽  
Sigma Subunit

ABSTRACT Escherichia coli cell viability during starvation is strongly dependent on the expression of the rpoS gene, encoding the RpoS sigma subunit of RNA polymerase. RpoS abundance has been reported to be regulated at many levels, including transcription initiation, translation, and protein stability. The regulatory RNA SsrA (or tmRNA) has both tRNA and mRNA activities, relieving ribosome stalling and cotranslationally tagging proteins. We report here that SsrA is needed for the correct high-level translation of RpoS. The ATP-dependent protease Lon was also found to negatively affect RpoS translation, but only at low temperature. We suggest that SsrA may indirectly improve RpoS translation by limiting ribosome stalling and depletion of some component of the translation machinery.

Gene cloning and characterization of thiourocanate hydratase from Burkholderia sp. HME13

2019 ◽  
Vol 167 (3) ◽  
pp. 333-341
Author(s):  
Hisashi Muramatsu ◽  
Haruna Miyaoku ◽  
Syuya Kurita ◽  
Hidenori Matsuo ◽  
Takehiro Kashiwagi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Crude Extract ◽  
Maximum Activity ◽  
Luria Bertani ◽  
Sole Nitrogen Source ◽  
Gene Encoding ◽  
Gene Cloning And Characterization

Abstract A novel enzyme, thiourocanate hydratase, which catalyses the conversion of thiourocanic acid to 3-(5-oxo-2-thioxoimidazolidin-4-yl) propionic acid, was isolated from the ergothioneine-utilizing strain, Burkholderia sp. HME13. When the HME13 cells were cultured in medium containing ergothioneine as the sole nitrogen source, thiourocanate-metabolizing activity was detected in the crude extract from the cells. However, activity was not detected in the crude extract from HME13 cells that were cultured in Luria-Bertani medium. The gene encoding thiourocanate hydratase was cloned and expressed in Escherichia coli, and the recombinant enzyme was purified to homogeneity. The enzyme showed maximum activity at pH 7.5 and 55°C and was stable between pH 5.0 and 10.5, and at temperatures up to 45°C. The Km and Vmax values of thiourocanate hydratase towards thiourocanic acid were 30 μM and 7.1 μmol/min/mg, respectively. The enzyme was strongly inhibited by CuCl2 and HgCl2. The amino acid sequence of the enzyme showed 46% identity to urocanase from Pseudomonas putida, but thiourocanate hydratase had no urocanase activity.

scholarly journals Slipped-Strand Mispairing Can Function as a Phase Variation Mechanism in Escherichia coli

2003 ◽  
Vol 185 (23) ◽  
pp. 6990-6994 ◽  
Author(s):  
Joshua Torres-Cruz ◽  
Marjan W. van der Woude
Keyword(s):  
Escherichia Coli ◽  
Haemophilus Influenzae ◽  
Reporter Gene ◽  
Phase Variation ◽  
Biologically Relevant ◽  
E Coli ◽  
Variation Mechanism ◽  
Relevant Range

ABSTRACT Slipped-strand mispairing (SSM) has not been identified as a mechanism of phase variation in Escherichia coli. Using a reporter gene, we show that sequences that cause phase variation by SSM in Haemophilus influenzae also lead to phase variation when introduced onto the chromosome of E. coli, and the frequencies of switching are in the biologically relevant range. Thus, the absence of SSM-mediated phase variation in E. coli does not appear to be due to a mechanistic constraint.

scholarly journals Escherichia coli exonuclease VII. Cloning and sequencing of the gene encoding the large subunit (xseA).

1986 ◽  
Vol 261 (32) ◽  
pp. 14929-14935
Author(s):  
J W Chase ◽  
B A Rabin ◽  
J B Murphy ◽  
K L Stone ◽  
K R Williams
Keyword(s):  
Escherichia Coli ◽  
Large Subunit ◽  
Cloning And Sequencing ◽  
Gene Encoding ◽  
Exonuclease Vii

scholarly journals Identification of the Gene Encoding Sulfopyruvate Decarboxylase, an Enzyme Involved in Biosynthesis of Coenzyme M

2000 ◽  
Vol 182 (17) ◽  
pp. 4862-4867 ◽  
Author(s):  
Marion Graupner ◽  
Huimin Xu ◽  
Robert H. White
Keyword(s):  
Escherichia Coli ◽  
Second Step ◽  
Gene Products ◽  
Methanococcus Jannaschii ◽  
Coenzyme M ◽  
Gene Encoding ◽  
Fourth Step

ABSTRACT The products of two adjacent genes in the chromosome ofMethanococcus jannaschii are similar to the amino and carboxyl halves of phosphonopyruvate decarboxylase, the enzyme that catalyzes the second step of fosfomycin biosynthesis inStreptomyces wedmorensis. These two M. jannaschii genes were recombinantly expressed inEscherichia coli, and their gene products were tested for the ability to catalyze the decarboxylation of a series of α-ketoacids. Both subunits are required to form an α6β6 dodecamer that specifically catalyzes the decarboxylation of sulfopyruvic acid to sulfoacetaldehyde. This transformation is the fourth step in the biosynthesis of coenzyme M, a crucial cofactor in methanogenesis and aliphatic alkene metabolism. The M. jannaschiisulfopyruvate decarboxylase was found to be inactivated by oxygen and reactivated by reduction with dithionite. The two subunits, designated ComD and ComE, comprise the first enzyme for the biosynthesis of coenzyme M to be described.

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