Nucleotide Sequences and Characterization of liv Genes Encoding Components of the High-Affinity Branched-Chain Amino Acid Transport System in Salmonella typhimurium1

Matsubara, Keiko; Ohnishi, Kouhei; Kiritani, Kazuyoshi

doi:10.1093/oxfordjournals.jbchem.a123872

Cited by 21 publications

(12 citation statements)

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“…Finally, an ABC transport system ATPase component and an extracellular sugar-binding protein resulted downregulated in LP. These two proteins share conserved domains with LivG/F ATPases and MalE, respectively, which are shown to be required for the up-take of alternative carbon sources during glucose limitation/starvation [35,36]. …”

Section: Resultsmentioning

confidence: 99%

Differential proteomic analysis highlights metabolic strategies associated with balhimycin production in Amycolatopsis balhimycina chemostat cultivations

et al. 2010

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BackgroundProteomics was recently used to reveal enzymes whose expression is associated with the production of the glycopeptide antibiotic balhimycin in Amycolatopsis balhimycina batch cultivations. Combining chemostat fermentation technology, where cells proliferate with constant parameters in a highly reproducible steady-state, and differential proteomics, the relationships between physiological status and metabolic pathways during antibiotic producing and non-producing conditions could be highlighted.ResultsTwo minimal defined media, one with low Pi (0.6 mM; LP) and proficient glucose (12 g/l) concentrations and the other one with high Pi (1.8 mM) and limiting (6 g/l; LG) glucose concentrations, were developed to promote and repress antibiotic production, respectively, in A. balhimycina chemostat cultivations. Applying the same dilution rate (0.03 h-1), both LG and LP chemostat cultivations showed a stable steady-state where biomass production yield coefficients, calculated on glucose consumption, were 0.38 ± 0.02 and 0.33 ± 0.02 g/g (biomass dry weight/glucose), respectively. Notably, balhimycin was detected only in LP, where quantitative RT-PCR revealed upregulation of selected bal genes, devoted to balhimycin biosynthesis, and of phoP, phoR, pstS and phoD, known to be associated to Pi limitation stress response. 2D-Differential Gel Electrophoresis (DIGE) and protein identification, performed by mass spectrometry and computer-assisted 2 D reference-map http://www.unipa.it/ampuglia/Abal-proteome-maps matching, demonstrated a differential expression for proteins involved in many metabolic pathways or cellular processes, including central carbon and phosphate metabolism. Interestingly, proteins playing a key role in generation of primary metabolism intermediates and cofactors required for balhimycin biosynthesis were upregulated in LP. Finally, a bioinformatic approach showed PHO box-like regulatory elements in the upstream regions of nine differentially expressed genes, among which two were tested by electrophoresis mobility shift assays (EMSA).ConclusionIn the two chemostat conditions, used to generate biomass for proteomic analysis, mycelia grew with the same rate and with similar glucose-biomass conversion efficiencies. Global gene expression analysis revealed a differential metabolic adaptation, highlighting strategies for energetic supply and biosynthesis of metabolic intermediates required for biomass production and, in LP, for balhimycin biosynthesis. These data, confirming a relationship between primary metabolism and antibiotic production, could be used to increase antibiotic yield both by rational genetic engineering and fermentation processes improvement.

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Section: Resultsmentioning

confidence: 99%

Differential proteomic analysis highlights metabolic strategies associated with balhimycin production in Amycolatopsis balhimycina chemostat cultivations

et al. 2010

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“…This transport is pH-dependent, H÷-independent and electrogenic. Genetic characterization of the carrier (Matsubara et al, 1992), determination of leucine-specific binding proteins (Williamson and Oxender, 1990) and the analysis of the amino acid sequence of the leucine carrier (Adams et al, 1990;Hoshino et al, 1992) are described. Glutamine is transported via at least two different carrier systems in the kidney (Weiss, 1978).…”

Section: Introductionmentioning

confidence: 99%

Stimulation of renal amino acid reabsorption after treatment with triiodothyronine or dexamethasone in amino acid loaded rats

1997

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Summary.In adult female anaestetized rats, the influence of triiodothyronine or dexamethasone on renal amino acid handling was investigated in leucine (20mg/100g b.wt.) or glutamine (45mg/100g b.wt.) loaded animals. Bolus injections of both amino acids were followed by temporary increase in fractional excretion of the administered amino acids as well of the endogenous amino acids which were not administered.Under load conditions (leucine and glutamine), dexamethasone treatment (60/~g/100 g b.wt. for 3 days, i.p. once daily) was followed by a stimulation of renal amino acid reabsorption. The increase in fractional amino acid excretion after amino acid load was significantly lower than in untreated rats. The effect of triiodothyronine (20/~g/100 g b.wt. for 3 days, i.p. once daily) was different in leucine and glutamine loaded animals: after leucine bolus injection a comparable stimulatory effect as shown for dexamethasone could be demonstrated, but after glutamine administration the stimulatory action of T3 was masked. T3 even increases fractional amino acid excretion in glutamine loaded rats as a sign of enhanced "house-keeping" in the renal tubular cells. These results confirm previous findings and indicate different effects of both hormones on the renal handling of amino acids.

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“…The branched-chain amino acids (BCAAs; Ile, Leu, and Val) are hydrophobic amino acids typically found in the core in globular proteins or in the transmembrane domain in cell surface proteins (5). The transport mechanisms described for acquisition of the BCAAs in bacteria include secondary transporters belonging to the Leu, Ile, Val:cation symporter (LIVCS) family (e.g., BrnQ, BraB, BraZ, and BcaP) (4,(6)(7)(8)(9) and the LIV-I ABC transporter (10)(11)(12)(13). With the exception of an ABC transporter in Streptococcus pneumoniae (14), secondary transport, which couples the movement of an ion, usually Na ϩ or H ϩ , down its concentration gradient with the movement of another molecule against its concentration gradient, is the primary means of BCAA acquisition in Gram-positive bacteria.…”

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confidence: 99%

Role of BrnQ1 and BrnQ2 in Branched-Chain Amino Acid Transport and Virulence in Staphylococcus aureus

et al. 2015

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The branched-chain amino acids (BCAAs; Ile, Leu, and Val) not only are important nutrients for the growth of Staphylococcus aureus but also are corepressors for CodY, which regulates virulence gene expression, implicating BCAAs as an important link between the metabolic state of the cell and virulence. BCAAs are either synthesized intracellularly or acquired from the environment. S. aureus encodes three putative BCAA transporters, designated BrnQ1, BrnQ2, and BrnQ3; their functions have not yet been formally tested. In this study, we mutated all three brnQ paralogs so as to characterize their substrate specificities and their roles in growth in vitro and in vivo. We demonstrated that in the community-associated, methicillin-resistant S. aureus (CA-MRSA) strain USA300, BrnQ1 is involved in uptake of all three BCAAs, BrnQ2 transports Ile, and BrnQ3 does not have a significant role in BCAA transport under the conditions tested. Of the three, only BrnQ1 is essential for USA300 to grow in a chemically defined medium that is limited for Leu or Val. Interestingly, we observed that a brnQ2 mutant grew better than USA300 in media limited for Leu and Val, owing to the fact that this mutation leads to overexpression of brnQ1. In a murine infection model, the brnQ1 mutant was attenuated, but in contrast, brnQ2 mutants had significantly increased virulence compared to that of USA300, a phenotype we suggest is at least partially linked to enhanced in vivo scavenging of Leu and Val through BrnQ1. These data uncover a hitherto-undiscovered connection between nutrient acquisition and virulence in CA-MRSA. Staphylococcus aureus is a highly successful human pathogen that succeeds at infecting virtually every body site, causing skin, soft tissue, respiratory, bone, joint, and endovascular infections (1). Maintenance of metabolic homeostasis is important for its infection process, as the majority of genes necessary for infection identified in large-scale signature-tagged mutagenesis (STM) screens fall into the categories of metabolism, transport, and biosynthesis (2, 3). Acquisition of host-derived nutrients, specifically amino acids, appears to be an important mechanism of meeting nutritional needs, as a large proportion of attenuated STM strains contain mutations in amino acid transporters (3).Amino acid transporters are ubiquitous in bacteria and are typically selective for transporting either one amino acid or several amino acids with related structures (4). The branched-chain amino acids (BCAAs; Ile, Leu, and Val) are hydrophobic amino acids typically found in the core in globular proteins or in the transmembrane domain in cell surface proteins (5). The transport mechanisms described for acquisition of the BCAAs in bacteria include secondary transporters belonging to the Leu, Ile, Val:cation symporter (LIVCS) family (e.g., BrnQ, BraB, BraZ, and BcaP) (4, 6-9) and the LIV-I ABC transporter (10-13). With the exception of an ABC transporter in Streptococcus pneumoniae (14), secondary transport, which couples the movement of an ion...

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Nucleotide Sequences and Characterization of liv Genes Encoding Components of the High-Affinity Branched-Chain Amino Acid Transport System in Salmonella typhimurium1

Cited by 21 publications

References 0 publications

Differential proteomic analysis highlights metabolic strategies associated with balhimycin production in Amycolatopsis balhimycina chemostat cultivations

Differential proteomic analysis highlights metabolic strategies associated with balhimycin production in Amycolatopsis balhimycina chemostat cultivations

Stimulation of renal amino acid reabsorption after treatment with triiodothyronine or dexamethasone in amino acid loaded rats

Role of BrnQ1 and BrnQ2 in Branched-Chain Amino Acid Transport and Virulence in Staphylococcus aureus

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