<i>TKL2</i>, a second transketolase gene of <i>Saccharomyces cerevisiae</i>

Schaaff-Gerstenschläger, Ine; Mannhaupt, Gertrud; Vetter, I.R.; Zimmermann, Friedrich K.; Feldmann, Horst

doi:10.1111/j.1432-1033.1993.tb18268.x

Cited by 63 publications

(39 citation statements)

References 30 publications

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“…4A; maximum fermentation rates, 200.2 ml/6 h for wild-type strain X2180-1A and 197.8 ml/6 h for the zwf1⌬ mutant). In contrast, the fermentation rate of the tkl1/2⌬ tal1⌬ triple disruptant, in which the nonoxidative branch of the pentose phosphate pathway is inhibited (31,32), was extremely low ( Fig. 4B; fermentation rate for the tkl1/2⌬ tal1⌬ strain, 77.4 ml/6 h).…”

Section: Fermentation Kinetics and Carbon Metabolic Profile Of Rim15⌬mentioning

confidence: 80%

Inhibitory Role of Greatwall-Like Protein Kinase Rim15p in Alcoholic Fermentation via Upregulating the UDP-Glucose Synthesis Pathway in Saccharomyces cerevisiae

Watanabe

Zhou

Hirata

et al. 2016

Appl Environ Microbiol

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The high fermentation rate of Saccharomyces cerevisiae sake yeast strains is attributable to a loss-of-function mutation in the RIM15 gene, which encodes a Greatwall-family protein kinase that is conserved among eukaryotes. In the present study, we performed intracellular metabolic profiling analysis and revealed that deletion of the RIM15 gene in a laboratory strain impaired glucose-anabolic pathways through the synthesis of UDP-glucose (UDPG). Although Rim15p is required for the synthesis of trehalose and glycogen from UDPG upon entry of cells into the quiescent state, we found that Rim15p is also essential for the accumulation of cell wall ␤-glucans, which are also anabolic products of UDPG. Furthermore, the impairment of UDPG or 1,3-␤-glucan synthesis contributed to an increase in the fermentation rate. Transcriptional induction of PGM2 (phosphoglucomutase) and UGP1 (UDPG pyrophosphorylase) was impaired in Rim15p-deficient cells in the early stage of fermentation. These findings demonstrate that the decreased anabolism of glucose into UDPG and 1,3-␤-glucan triggered by a defect in the Rim15p-mediated upregulation of PGM2 and UGP1 redirects the glucose flux into glycolysis. Consistent with this, sake yeast strains with defective Rim15p exhibited impaired expression of PGM2 and UGP1 and decreased levels of ␤-glucans, trehalose, and glycogen during sake fermentation. We also identified a sake yeast-specific mutation in the glycogen synthesis-associated glycogenin gene GLG2, supporting the conclusion that the glucose-anabolic pathway is impaired in sake yeast. These findings demonstrate that downregulation of the UDPG synthesis pathway is a key mechanism accelerating alcoholic fermentation in industrially utilized S. cerevisiae sake strains. S ake yeast strains, which belong to the species Saccharomyces cerevisiae, are capable of achieving ethanol yields as high as 22 vol% in fermenting sake mash (1-3). This characteristic phenotype is attributed in part to their high and sustained maximum fermentation rates, as observed in batch cultures containing high concentrations of glucose (4), and is due to the continuous supply of fermentable sugars to yeast cells in sake mash via the degradation of rice starch by enzymes produced by Aspergillus oryzae. In recent studies of the representative sake yeast strain Kyokai no. 7 (K7) and its relatives, we revealed that several stress-and/or nutrient-responsive transcription factors, particularly Msn2p and Msn4p (Msn2/4p), Hsf1p, Adr1p, and Cat8p, are significantly inactivated (5-7). Impairment of these transcriptional activators in laboratory strains of S. cerevisiae leads to increased fermentation rates, indicating that defective stress responses are linked with the superior fermentation properties of sake yeast (2, 5-7). Moreover, a loss-of-function mutation by insertion of an A residue at position 5055 in the RIM15 gene (rim15 5055insA ) was commonly found among K7-related strains (8). RIM15 encodes a conserved Greatwall-like protein kinase involved in the control of mitot...

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Section: Fermentation Kinetics and Carbon Metabolic Profile Of Rim15⌬mentioning

confidence: 80%

Inhibitory Role of Greatwall-Like Protein Kinase Rim15p in Alcoholic Fermentation via Upregulating the UDP-Glucose Synthesis Pathway in Saccharomyces cerevisiae

Watanabe

Zhou

Hirata

et al. 2016

Appl Environ Microbiol

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“…Strain KS114 was obtained by deleting the TAL1 gene of 1783 using the gene replacement plasmid p⌬TAL1:LEU2 (20). Strains KS115 and KS116 were constructed by introducing the TKL1 or TKL2 replacement plasmids p⌬TKL1:URA3 (21) or p⌬TKL2:LEU2 (22), respectively, into strain 1783. Strains KS109, KS121, and KS122 were obtained by deleting the PMR1 gene of strains KS105, KS113, and KS117, respectively, using the PMR1 replacement plasmid PL119 (14).…”

Section: Methodsmentioning

confidence: 99%

The Yeast Copper/Zinc Superoxide Dismutase and the Pentose Phosphate Pathway Play Overlapping Roles in Oxidative Stress Protection

Slekar

Kosman

Culotta

1996

Journal of Biological Chemistry

200

155

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In Saccharomyces cerevisiae, loss of cytosolic superoxide dismutase (Sod1) results in several air-dependent mutant phenotypes, including methionine auxotrophy and oxygen sensitivity. Here we report that these two sod1⌬ phenotypes were specifically suppressed by elevated expression of the TKL1 gene, encoding transketolase of the pentose phosphate pathway. The apparent connection between Sod1 and the pentose phosphate pathway prompted an investigation of mutants defective in glucose-6-phosphate dehydrogenase (Zwf1), which catalyzes the rate-limiting NADPH-producing step of this pathway. We confirmed that zwf1⌬ mutants are methionine auxotrophs and report that they also are oxygen-sensitive. We determined that a functional ZWF1 gene product was required for TKL1 to suppress sod1⌬, leading us to propose that increased flux through the oxidative reactions of the pentose phosphate pathway can rescue sod1 methionine auxotrophy. To better understand this methionine growth requirement, we examined the sulfur compound requirements of sod1⌬ and zwf1⌬ mutants, and noted that these mutants exhibit the same apparent defect in sulfur assimilation. Our studies suggest that this defect results from the impaired redox status of aerobically grown sod1 and zwf1 mutants, implicating Sod1 and the pentose phosphate pathway as being critical for maintenance of the cellular redox state.Aerobic organisms are constantly exposed to potentially harmful reactive oxygen species that are generated as byproducts of cellular metabolism. These oxygen free radicals have the potential to damage critical cellular components such as DNA, proteins, and lipids (see Refs. 1 and 2 for review). However, aerobic organisms have evolved with both enzymatic and non-enzymatic oxidant defense mechanisms that are designed for protection against such assaults. Non-enzymatic defenses include the tripeptide glutathione (GSH) and the small peptide thioredoxin (Trx), while enzymatic defenses include catalases, peroxidases, and superoxide dismutases (Ref.

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“…1) (21). The regulation and roles of the major and minor transketolases in bacteria and S. cerevisiae are not well understood (8, 13-15, 21, 23).…”

Section: -Phosphate (mentioning

confidence: 99%

“…The cellular activity of the TktB isoenzyme, which shows 74% amino acid identity with the TktA protein, appears to be very low, at least in the few growth conditions tested so far (13). Similarly, there are two transketolase isoenzymes in Saccharomyces cerevisiae (21,23). We tested the validity of the pathway in Fig.…”

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confidence: 99%

An Escherichia coli K-12 tktA tktB mutant deficient in transketolase activity requires pyridoxine (vitamin B6) as well as the aromatic amino acids and vitamins for growth

Zhao

Winkler

1994

J Bacteriol

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We show that a tktA tktB double mutant, which is devoid of the two known transketolase isoenzymes of Escherichia coli K-12, requires pyridoxine (vitamin B6) as well as the aromatic amino acids and vitamins for growth. This pyridoxine requirement can also be satisfied by 4-hydroxy-L-threonine or glycolaldehyde. These results provide direct evidence that D-erythrose-4-phosphate is a precursor of the pyridine ring of pyridoxine.In addition, they show that the two major E. coli transketolase isoenzymes are not required for the biosynthesis of D-1-deoxyxylulose, which is thought to be another precursor of pyridoxine.

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TKL2, a second transketolase gene of Saccharomyces cerevisiae

Cited by 63 publications

References 30 publications

Inhibitory Role of Greatwall-Like Protein Kinase Rim15p in Alcoholic Fermentation via Upregulating the UDP-Glucose Synthesis Pathway in Saccharomyces cerevisiae

Inhibitory Role of Greatwall-Like Protein Kinase Rim15p in Alcoholic Fermentation via Upregulating the UDP-Glucose Synthesis Pathway in Saccharomyces cerevisiae

The Yeast Copper/Zinc Superoxide Dismutase and the Pentose Phosphate Pathway Play Overlapping Roles in Oxidative Stress Protection

An Escherichia coli K-12 tktA tktB mutant deficient in transketolase activity requires pyridoxine (vitamin B6) as well as the aromatic amino acids and vitamins for growth

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