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Trp operon

Scot P Ouellette, Parker R Messerli, Nicholas A Wood, Heather Hajovsky
As an obligate intracellular, developmentally regulated bacterium, Chlamydia is sensitive to amino acid fluctuations within its host cell. When human epithelial cells are treated with the cytokine interferon-γ (IFNγ), the tryptophan (trp)-degrading enzyme, indoleamine-2,3-dioxygenase, is induced. Chlamydiae within such cells are starved for trp and enter a state of so-called persistence. Chlamydia lacks the stringent response used by many eubacteria to respond to this stress. Unusually, chlamydial transcription is globally elevated during trp starvation with transcripts for trp-codon containing genes disproportionately increased...
April 30, 2018: Infection and Immunity
M Mominul Islam, Martina Jelocnik, Wilhelmina M Huston, Peter Timms, Adam Polkinghorne
Chlamydia pecorum is an important intracellular bacterium that causes a range of diseases in animals, including a native Australian marsupial, the koala. In humans and animals, a gamma interferon (IFN-γ)-mediated immune response is important for the control of intracellular bacteria. The present study tested the hypotheses that C. pecorum can escape IFN-γ-mediated depletion of host cell tryptophan pools. In doing so, we demonstrated that, unlike Chlamydia trachomatis , C. pecorum is completely resistant to IFN-γ in human epithelial cells...
April 2018: Infection and Immunity
Hiroya Tomita, Yohei Katsuyama, Hiromichi Minami, Yasuo Ohnishi
Rufomycin is a circular heptapeptide with anti-mycobacterial activity and is produced by Streptomyces atratus ATCC 14046. Its structure contains three non-proteinogenic amino acids, N -dimethylallyltryptophan, trans -2-crotylglycine, and 3-nitrotyrosine (3NTyr). Although the rufomycin structure was already reported in the 1960s, its biosynthesis, including 3NTyr generation, remains unclear. To elucidate the rufomycin biosynthetic pathway, we assembled a draft genome sequence of S. atratus and identified the rufomycin biosynthetic gene cluster ( ruf cluster), consisting of 20 ORFs ( rufA-rufT )...
September 22, 2017: Journal of Biological Chemistry
Alexander Nieß, Michael Löffler, Joana D Simen, Ralf Takors
Rapidly changing concentrations of substrates frequently occur during large-scale microbial cultivations. These changing conditions, caused by large mixing times, result in a heterogeneous population distribution. Here, we present a powerful and efficient modeling approach to predict the influence of varying substrate levels on the transcriptional and translational response of the cell. This approach consists of two parts, a single-cell model to describe transcription and translation for an exemplary operon (trp operon) and a second part to characterize cell distribution during the experimental setup...
2017: Frontiers in Microbiology
Smarajit Mondal, Alexander V Yakhnin, Paul Babitzke
The Bacillus subtilis trpEDCFBA operon is regulated by a transcription attenuation mechanism in which tryptophan-activated TRAP binds to the nascent transcript and blocks the formation of an antiterminator structure such that the formation of an overlapping intrinsic terminator causes termination in the 5' untranslated region (5' UTR). In the absence of bound TRAP, the antiterminator forms and transcription continues into the trp genes. RNA polymerase pauses at positions U107 and U144 in the 5' UTR. The general transcription elongation factors NusA and NusG stimulate pausing at both positions...
July 15, 2017: Journal of Bacteriology
Natalie M McAdams, Andrea Patterson, Paul Gollnick
Transcription of the tryptophan ( trp ) operon in Bacillus subtilis is regulated by an attenuation mechanism. Attenuation is controlled by the <u> t </u> rp <u>R</u>NA-binding <u>a</u>ttenuation <u>p</u>rotein (TRAP). TRAP binds to a site in the 5' leader region of the nascent trp transcript in response to the presence of excess intracellular tryptophan. This binding induces transcription termination upstream of the structural genes of the operon. In prior attenuation models, the role of TRAP was only to alter the secondary structure of the leader region RNA so as to promote formation of the trp attenuator, which was presumed to function as an intrinsic terminator...
March 15, 2017: Journal of Bacteriology
Paul Dallaire, François Major
We created an accelerated version of MC-Fold called MC-Flashfold that allows us to compute large numbers of competing secondary structures including noncanonical base pairs. We visualize the base pairs in these sets using high quality intuitive dot plots and arc plots. Our new tools allow us to explore RNA dynamics by visualizing the competing structures in free energy bands. Here we describe how to use these tools to generate dot plots that reveal the postulated anti-terminator stem in the E. coli trp operon leader sequence...
2016: Methods in Molecular Biology
Qassim Esmaeel, Mickael Chevalier, Gabrielle Chataigné, Rathinasamy Subashkumar, Philippe Jacques, Valérie Leclère
Based on the exploration of data generated by genome sequencing, a bioinformatics approach has been chosen to identify the biosynthetic pathway of the siderophores produced by Aeromonas species. The amonabactins, considered as a virulence factor, represent a family of four variants of catechol peptidic siderophores containing Dhb, Lys, Gly, and an aromatic residue either Trp or Phe in a D-configuration. The synthesis operon is constituted of seven genes named amoCEBFAGH and is iron-regulated. The cluster includes genes encoding proteins involved in the synthesis and incorporation of the Dhb monomer, and genes encoding specific nonribosomal peptide synthetases, which are responsible for the building of the peptidic moiety...
October 2016: Applied Microbiology and Biotechnology
Ugo Cenci, Mathieu Ducatez, Derifa Kadouche, Christophe Colleoni, Steven G Ball
Chlamydiales were recently proposed to have sheltered the future cyanobacterial ancestor of plastids in a common inclusion. The intracellular pathogens are thought to have donated those critical transporters that triggered the efflux of photosynthetic carbon and the consequent onset of symbiosis. Chlamydiales are also suspected to have encoded glycogen metabolism TTS (Type Three Secretion) effectors responsible for photosynthetic carbon assimilation in the eukaryotic cytosol. We now review the reasons underlying other chlamydial lateral gene transfers evidenced in the descendants of plastid endosymbiosis...
2016: Frontiers in Cellular and Infection Microbiology
Scot P Ouellette, Kelsey J Rueden, Elizabeth A Rucks
In evolving to an obligate intracellular niche, Chlamydia has streamlined its genome by eliminating superfluous genes as it relies on the host cell for a variety of nutritional needs like amino acids. However, Chlamydia can experience amino acid starvation when the human host cell in which the bacteria reside is exposed to interferon gamma (IFN-γ), which leads to a tryptophan (Trp)-limiting environment via induction of the enzyme indoleamine-2,3-dioxygenase (IDO). The stringent response is used to respond to amino acid starvation in most bacteria but is missing from Chlamydia Thus, how Chlamydia, a Trp auxotroph, responds to Trp starvation in the absence of a stringent response is an intriguing question...
September 2016: Infection and Immunity
Christoph Feinauer, Hendrik Szurmant, Martin Weigt, Andrea Pagnani
Interaction between proteins is a fundamental mechanism that underlies virtually all biological processes. Many important interactions are conserved across a large variety of species. The need to maintain interaction leads to a high degree of co-evolution between residues in the interface between partner proteins. The inference of protein-protein interaction networks from the rapidly growing sequence databases is one of the most formidable tasks in systems biology today. We propose here a novel approach based on the Direct-Coupling Analysis of the co-evolution between inter-protein residue pairs...
2016: PloS One
Zijing Chen, Hsiang-Chin Chen, Craig Montell
TRP channels and G protein-coupled receptors (GPCRs) play critical roles in sensory reception. However, the identities of the chaperones that assist GPCRs in translocating from the endoplasmic reticulum (ER) are limited, and TRP ER chaperones are virtually unknown. The one exception for TRPs is Drosophila XPORT. Here, we show that the xport locus is bicistronic and encodes unrelated transmembrane proteins, which enable the signaling proteins that initiate and culminate phototransduction, rhodopsin 1 (Rh1) and TRP, to traffic to the plasma membrane...
October 20, 2015: Cell Reports
Guang-Huey Lin, Hao-Ping Chen, Hung-Yu Shu
Indole, a derivative of the amino acid tryptophan, is a toxic signaling molecule, which can inhibit bacterial growth. To overcome indole-induced toxicity, many bacteria have developed enzymatic defense systems to convert indole to non-toxic, water-insoluble indigo. We previously demonstrated that, like other aromatic compound-degrading bacteria, Acinetobacter baumannii can also convert indole to indigo. However, no work has been published investigating this mechanism. Here, we have shown that the growth of wild-type A...
2015: PloS One
Guojie Zhao, Tianyu Hu, Jun Li, Hua Wei, Hong Shang, Yifu Guan
Rolling circle amplification (RCA) has been considered as a powerful tool for nucleic acids detection. Here, a novel repressor-RCA-based method for L-tryptophan (L-Trp) detection was developed. This method utilizes the specific interaction between the RCA circular template and the Trp repressor protein (TrpR) involved in trp operon of Escherichia coli (E. coli). In the absence of L-Trp, the TrpR protein could not bind to the RCA template, and the RCA process can be continued. When L-Trp is present, the activated TrpR will bind to the operon sequence on the RCA template and inhibit the RCA reaction...
September 15, 2015: Biosensors & Bioelectronics
Jonatan C Campillo-Brocal, María Dolores Chacón-Verdú, Patricia Lucas-Elío, Antonio Sánchez-Amat
BACKGROUND: L-Amino acid oxidases (LAOs) have been generally described as flavoproteins that oxidize amino acids releasing the corresponding ketoacid, ammonium and hydrogen peroxide. The generation of hydrogen peroxide gives to these enzymes antimicrobial characteristics. They are involved in processes such as biofilm development and microbial competition. LAOs are of great biotechnological interest in different applications such as the design of biosensors, biotransformations and biomedicine...
2015: BMC Genomics
Thomas J D Coulson, Cheryl L Patten
The TyrR transcription factor regulates genes involved in the uptake and biosynthesis of aromatic amino acids in Enterobacteriaceae. Genes may be positively or negatively regulated depending on the presence or absence of each aromatic amino acid, all three of which function as cofactors for TyrR. In this report we detail the transcriptional control of two divergently transcribed genes, akr and ipdC, by TyrR, elucidated by promoter fusion expression assays and electrophoretic mobility shift assays to assess protein-DNA interactions...
2015: PloS One
Lampet Wongsaroj, Ratiboot Sallabhan, James M Dubbs, Skorn Mongkolsuk, Suvit Loprasert
Indirubin is a strong inhibitor of several eukaryotic cell signaling pathways and shows promise as a treatment for myelocytic leukemia and Alzheimer's disease. The tmoABCDEF operon, encoding the components of a novel toluene 4-monooxygenase from the paint factory soil isolate, Pseudomonas sp. M4, was cloned and expressed in Escherichia coli. E. coli::pKSR12 expressing the tmo genes was used to develop a two-phase [dioctyl phthalate (DOP)/aqueous medium] culture system that was optimized to obtain maximal yields of indirubin from the starting substrate, indole...
August 2015: Molecular Biotechnology
Jing Yun A Zhu, Irmtraud M Meyer
Protein-coding and non-coding RNA transcripts perform a wide variety of cellular functions in diverse organisms. Several of their functional roles are expressed and modulated via RNA structure. A given transcript, however, can have more than a single functional RNA structure throughout its life, a fact which has been previously overlooked. Transient RNA structures, for example, are only present during specific time intervals and cellular conditions. We here introduce four RNA families with transient RNA structures that play distinct and diverse functional roles...
2015: RNA Biology
Dawn L Taylor, Vanessa M Ante, X Renee Bina, Mondraya F Howard, James E Bina
Vibrio cholerae encodes six resistance-nodulation-division (RND) efflux systems which function in antimicrobial resistance, virulence factor production, and intestinal colonization. Among the six RND efflux systems, VexAB exhibited broad substrate specificity and played a predominant role in intrinsic antimicrobial resistance. The VexAB system was encoded in an apparent three gene operon that included vexR; which encodes an uncharacterized TetR family regulator. In this work we examined the role of vexR in vexRAB expression...
2015: PloS One
Soo-Kyoung Kim, Ha-Young Park, Joon-Hee Lee
Anthranilate and indole are alternative degradation products of tryptophan, depending on the bacterial species. While indole enhances the biofilm formation of Pseudomonas aeruginosa, we found that anthranilate, the tryptophan degradation product of P. aeruginosa, had an opposite effect on P. aeruginosa biofilm formation, in which anthranilate deteriorated the mushroom structure of biofilm. The anthranilate effect on biofilm formation was differentially exerted depending on the developmental stage and the presence of shear force...
April 2015: Applied and Environmental Microbiology
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