Abstract
We have carried out a genetic analysis on pyruvate kinase (Pyk Tk) and phosphoenolpyruvate synthase (PpsTk) in the hyperthermophilic archaeon, Thermococcus kodakarensis. In principle, both enzymes can catalyse the final step of the modified Embden-Meyerhof (EM) pathway found in Thermococcales, the conversion of phosphoenolpyruvate (PEP) to pyruvate, with the former utilizing ADP, while the latter is dependent on AMP and phosphate. Enzyme activities and transcript levels of both PykTk, and PpsTk increased in T. kodakarensis under glycolytic conditions when compared with cells grown on pyruvate or amino acids. Using KW128, a tryptophan auxotrophic mutant with a trpE gene disruption, as a host strain, we obtained mutant strains with single gene disruptions in either the pyk Tk (Δpyk strain) or ppsTk (Δpps strain) gene. Specific growth rates and cell yields were examined in various media and compared with the host KW128 strain. The results indicated that both enzymes participated in pyruvate metabolism, but were not essential. In the presence of maltooligosaccharides, the Δpyk strain displayed a 15% decrease in growth rate compared with the host strain, indicating that PykTk does participate in glycolysis. However an even more dramatic effect was observed in the Δpps strain in that the strain could not grow at all on maltooligosaccharides. The results clearly indicate that, in contrast to the conventional EM pathway dependent on pyruvate kinase, PEP synthase is the essential enzyme for the glycolytic conversion of PEP to pyruvate in T. kodakarensis. The physiological roles of the two enzymes under various growth conditions are discussed.
| Original language | English |
|---|---|
| Pages (from-to) | 898-909 |
| Number of pages | 12 |
| Journal | Molecular Microbiology |
| Volume | 61 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Aug 2006 |
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ASJC Scopus subject areas
- Molecular Biology
- Microbiology
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Phosphoenolpyruvate synthase plays an essential role for glycolysis in the modified Embden-Meyerhof pathway in Thermococcus kodakarensis. / Imanaka, Hiroyuki; Yamatsu, Atsushi; Fukui, Toshiaki; Atomi, Haruyuki; Imanaka, Tadayuki.
In: Molecular Microbiology, Vol. 61, No. 4, 08.2006, p. 898-909.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Phosphoenolpyruvate synthase plays an essential role for glycolysis in the modified Embden-Meyerhof pathway in Thermococcus kodakarensis
AU - Imanaka, Hiroyuki
AU - Yamatsu, Atsushi
AU - Fukui, Toshiaki
AU - Atomi, Haruyuki
AU - Imanaka, Tadayuki
PY - 2006/8
Y1 - 2006/8
N2 - We have carried out a genetic analysis on pyruvate kinase (Pyk Tk) and phosphoenolpyruvate synthase (PpsTk) in the hyperthermophilic archaeon, Thermococcus kodakarensis. In principle, both enzymes can catalyse the final step of the modified Embden-Meyerhof (EM) pathway found in Thermococcales, the conversion of phosphoenolpyruvate (PEP) to pyruvate, with the former utilizing ADP, while the latter is dependent on AMP and phosphate. Enzyme activities and transcript levels of both PykTk, and PpsTk increased in T. kodakarensis under glycolytic conditions when compared with cells grown on pyruvate or amino acids. Using KW128, a tryptophan auxotrophic mutant with a trpE gene disruption, as a host strain, we obtained mutant strains with single gene disruptions in either the pyk Tk (Δpyk strain) or ppsTk (Δpps strain) gene. Specific growth rates and cell yields were examined in various media and compared with the host KW128 strain. The results indicated that both enzymes participated in pyruvate metabolism, but were not essential. In the presence of maltooligosaccharides, the Δpyk strain displayed a 15% decrease in growth rate compared with the host strain, indicating that PykTk does participate in glycolysis. However an even more dramatic effect was observed in the Δpps strain in that the strain could not grow at all on maltooligosaccharides. The results clearly indicate that, in contrast to the conventional EM pathway dependent on pyruvate kinase, PEP synthase is the essential enzyme for the glycolytic conversion of PEP to pyruvate in T. kodakarensis. The physiological roles of the two enzymes under various growth conditions are discussed.
AB - We have carried out a genetic analysis on pyruvate kinase (Pyk Tk) and phosphoenolpyruvate synthase (PpsTk) in the hyperthermophilic archaeon, Thermococcus kodakarensis. In principle, both enzymes can catalyse the final step of the modified Embden-Meyerhof (EM) pathway found in Thermococcales, the conversion of phosphoenolpyruvate (PEP) to pyruvate, with the former utilizing ADP, while the latter is dependent on AMP and phosphate. Enzyme activities and transcript levels of both PykTk, and PpsTk increased in T. kodakarensis under glycolytic conditions when compared with cells grown on pyruvate or amino acids. Using KW128, a tryptophan auxotrophic mutant with a trpE gene disruption, as a host strain, we obtained mutant strains with single gene disruptions in either the pyk Tk (Δpyk strain) or ppsTk (Δpps strain) gene. Specific growth rates and cell yields were examined in various media and compared with the host KW128 strain. The results indicated that both enzymes participated in pyruvate metabolism, but were not essential. In the presence of maltooligosaccharides, the Δpyk strain displayed a 15% decrease in growth rate compared with the host strain, indicating that PykTk does participate in glycolysis. However an even more dramatic effect was observed in the Δpps strain in that the strain could not grow at all on maltooligosaccharides. The results clearly indicate that, in contrast to the conventional EM pathway dependent on pyruvate kinase, PEP synthase is the essential enzyme for the glycolytic conversion of PEP to pyruvate in T. kodakarensis. The physiological roles of the two enzymes under various growth conditions are discussed.
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UR - http://www.scopus.com/inward/citedby.url?scp=33746546235&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2958.2006.05287.x
DO - 10.1111/j.1365-2958.2006.05287.x
M3 - Article
C2 - 16879645
AN - SCOPUS:33746546235
VL - 61
SP - 898
EP - 909
JO - Molecular Microbiology
JF - Molecular Microbiology
SN - 0950-382X
IS - 4
ER -