TAT1 Encodes a Low-Affinity Histidine Transporter inSaccharomyces cerevisiae

Bajmoczi, Milan; Sneve, Mary; Eide, David J.; Drewes, Lester R.

doi:10.1006/bbrc.1998.8082

Cited by 21 publications

(10 citation statements)

References 12 publications

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“…According to the MichaelisMenten equation, the K m and V max values of AroP for histidine were 11.40 Ϯ 2.03 M and 3.37 Ϯ 0.44 nmol/min/mg (DW), respectively (see Fig. S2 in the supplemental material), indicating that AroP has a much higher affinity than the low-affinity histidine transporters, such as AroP of S. Typhimurium (K m ϭ 100 M) (12) and TAT1 of Saccharomyces cerevisiae (K m ϭ 300 M) (40), and a lower affinity than the ABC-type specific histidine transporter HisJQMP of S. Typhimurium (K m ϭ 0.08 M) (12). Additionally, in C. glutamicum, the K m value of AroP for L-tyrosine was determined to be 3.0 Ϯ 0.3 M (28), which suggested a slightly higher affinity of AroP for L-tyrosine than for L-histidine.…”

Section: Resultsmentioning

confidence: 99%

Characterization and Molecular Mechanism of AroP as an Aromatic Amino Acid and Histidine Transporter in Corynebacterium glutamicum

Shang

Zhang

et al. 2013

Journal of Bacteriology

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bCorynebacterium glutamicum is equipped with abundant membrane transporters to adapt to a changing environment. Many amino acid transporters have been identified in C. glutamicum, but histidine uptake has not been investigated in detail. Here, we identified the aromatic amino acid transporter encoded by aroP as a histidine transporter in C. glutamicum by a combination of the growth and histidine uptake features. Characterization of histidine uptake showed that AroP has a moderate affinity for histidine, with a K m value of 11.40 ؎ 2.03 M, and histidine uptake by AroP is competitively inhibited by the aromatic amino acids. Among the four substrates, AroP exhibits a stronger preference for tryptophan than for tyrosine, phenylalanine, and histidine. Homology structure modeling and molecular docking were performed to predict the substrate binding modes and conformational changes during substrate transport. These results suggested that tryptophan is best accommodated in the binding pocket due to shape compatibility, strong hydrophobic interactions, and the lowest binding energy, which is consistent with the observed substrate preference of AroP. Furthermore, the missense mutations of the putative substrate binding sites verified that Ser24, Ala28, and Gly29 play crucial roles in substrate binding and are highly conserved in the Gram-positive bacteria. Finally, the expression of aroP is not significantly affected by extracellular histidine or aromatic amino acids, indicating that the physiological role of AroP may be correlated with the increased fitness of C. glutamicum to assimilate extracellular amino acid for avoiding the high energy cost of amino acid biosynthesis.

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Section: Resultsmentioning

confidence: 99%

Characterization and Molecular Mechanism of AroP as an Aromatic Amino Acid and Histidine Transporter in Corynebacterium glutamicum

Shang

Zhang

et al. 2013

Journal of Bacteriology

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“…(2) TAT1, encoding an amino acid transporter for valine, leucine, isoleucine and tyrosine, low-affinity tryptophan and histidine transporter (Schmidt et al, 1994;Bajmoczi et al, 1998;Regenberg et al, 1999).…”

Section: Strainsmentioning

confidence: 99%

Commonly usedSaccharomyces cerevisiaestrains (e.g. BY4741, W303) are growth sensitive on synthetic complete medium due to poor leucine uptake

Cohen

Engelberg

2007

FEMS Microbiology Letters

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It is reported that some of the widely used laboratory strains of Saccharomyces cerevisiae (e.g. W303, BY4741) are sensitive to synthetic media containing all 20 amino acids [e.g. synthetic complete (SC) medium or supplemented minimal medium]. To determine the molecular basis for this unexpected sensitivity, a genomic library was screened and three genes were identified that, when overexpressed, rescue cells from this phenotype. Two of the 'rescuing' genes, BAP2 and TAT1, are related to transport of leucine, and one, LEU2, to synthesis of leucine, showing that sensitivity to SC medium is associated with the leu2 mutation. The sensitive strains seem incapable of transporting leucine when grown on synthetic complete media. This effect of the leu2 mutation should be taken into consideration when analyzing the results of genetic screens and other experiments performed with these strains.

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“…Some previously characterized genes, such as MUP1 and MUP3 (38), TAT1 and TAT2 (9,75), and GNP1 (90), were also included in this analysis because the reported experiments on expression of these genes were carried out in complex medium or in minimal medium containing amino acids to compensate for amino acid auxotrophies, i.e., under conditions where the expression of Ssy1p-responsive genes should appear constitutive. In the RT-PCR experiments (Fig.…”

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confidence: 99%

Amino Acid Signaling in Saccharomyces cerevisiae: a Permease-Like Sensor of External Amino Acids and F-Box Protein Grr1p Are Required for Transcriptional Induction of the AGP1 Gene, Which Encodes a Broad-Specificity Amino Acid Permease

Iraqui

Vissers

Bernard

et al. 1999

Molecular and Cellular Biology

245

308

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The SSY1 gene of Saccharomyces cerevisiae encodes a member of a large family of amino acid permeases. Compared to the 17 other proteins of this family, however, Ssy1p displays unusual structural features reminiscent of those distinguishing the Snf3p and Rgt2p glucose sensors from the other proteins of the sugar transporter family. We show here that SSY1 is required for transcriptional induction, in response to multiple amino acids, of the AGP1 gene encoding a low-affinity, broad-specificity amino acid permease. Total noninduction of the AGP1 gene in the ssy1⌬ mutant is not due to impaired incorporation of inducing amino acids. Conversely, AGP1 is strongly induced by tryptophan in a mutant strain largely deficient in tryptophan uptake, but it remains unexpressed in a mutant that accumulates high levels of tryptophan endogenously. Induction of AGP1 requires Uga35p(Dal81p/DurLp), a transcription factor of the Cys 6 -Zn 2 family previously shown to participate in several nitrogen induction pathways. Induction of AGP1 by amino acids also requires Grr1p, the F-box protein of the SCF Grr1 ubiquitin-protein ligase complex also required for transduction of the glucose signal generated by the Snf3p and Rgt2p glucose sensors. Systematic analysis of amino acid permease genes showed that Ssy1p is involved in transcriptional induction of at least five genes in addition to AGP1. Our results show that the amino acid permease homologue Ssy1p is a sensor of external amino acids, coupling availability of amino acids to transcriptional events. The essential role of Grr1p in this amino acid signaling pathway lends further support to the hypothesis that this protein participates in integrating nutrient availability with the cell cycle.

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TAT1 Encodes a Low-Affinity Histidine Transporter inSaccharomyces cerevisiae

Cited by 21 publications

References 12 publications

Characterization and Molecular Mechanism of AroP as an Aromatic Amino Acid and Histidine Transporter in Corynebacterium glutamicum

Characterization and Molecular Mechanism of AroP as an Aromatic Amino Acid and Histidine Transporter in Corynebacterium glutamicum

Commonly usedSaccharomyces cerevisiaestrains (e.g. BY4741, W303) are growth sensitive on synthetic complete medium due to poor leucine uptake

Amino Acid Signaling in Saccharomyces cerevisiae: a Permease-Like Sensor of External Amino Acids and F-Box Protein Grr1p Are Required for Transcriptional Induction of the AGP1 Gene, Which Encodes a Broad-Specificity Amino Acid Permease

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