Abstract
Methionine synthase (EC2.1.1.14) catalyses the final step in methionine synthesis, i.e. methylation of homocysteine. A search of the Schizosaccharomyces pombe genomic database revealed a gene designated SPAC9.09, encoding a protein with significant homology to methionine synthase. Disruption of SPAC9.09 caused methionine auxotrophy, and thus the gene was identified as a methionine synthase and designated met26. The met26 mutant was found to exhibit a remarkable growth defect in the absence of adenine even in medium supplemented with methionine. This phenotype was not observed in other methionine auxotrophs. In the budding yeast Saccharomyces cerevisiae, which has been reported to utilize homocysteine in cysteine synthesis, lack of a functional methionine synthase did not cause a requirement for adenine. The introduction of genes from Sac. cerevisiae constituting the cystathionine pathway (CYS4 and CYS3) into Sch. pombe Δmet26 cells restored growth in the absence of adenine. HPLC analysis showed that total homocysteine content in Δmet26 cells was higher than in other methionine auxotrophs and that introduction of the Sac. cerevisiae cystathionine pathway decreased total homocysteine levels. These data demonstrate that accumulation of homocysteine causes a defect in purine biosynthesis in the met26 mutant.
| Original language | English |
|---|---|
| Pages (from-to) | 397-404 |
| Number of pages | 8 |
| Journal | Microbiology |
| Volume | 152 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Feb 1 2006 |
| Externally published | Yes |
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All Science Journal Classification (ASJC) codes
- Microbiology
Cite this
Homocysteine accumulation causes a defect in purine biosynthesis : Further characterization of Schizosaccharomyces pombe methionine auxotrophs. / Fujita, Yasuko; Ukena, Eiko; Iefuji, Haruyuki; Giga-Hama, Yuko; Takegawa, Kaoru.
In: Microbiology, Vol. 152, No. 2, 01.02.2006, p. 397-404.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Homocysteine accumulation causes a defect in purine biosynthesis
T2 - Further characterization of Schizosaccharomyces pombe methionine auxotrophs
AU - Fujita, Yasuko
AU - Ukena, Eiko
AU - Iefuji, Haruyuki
AU - Giga-Hama, Yuko
AU - Takegawa, Kaoru
PY - 2006/2/1
Y1 - 2006/2/1
N2 - Methionine synthase (EC2.1.1.14) catalyses the final step in methionine synthesis, i.e. methylation of homocysteine. A search of the Schizosaccharomyces pombe genomic database revealed a gene designated SPAC9.09, encoding a protein with significant homology to methionine synthase. Disruption of SPAC9.09 caused methionine auxotrophy, and thus the gene was identified as a methionine synthase and designated met26. The met26 mutant was found to exhibit a remarkable growth defect in the absence of adenine even in medium supplemented with methionine. This phenotype was not observed in other methionine auxotrophs. In the budding yeast Saccharomyces cerevisiae, which has been reported to utilize homocysteine in cysteine synthesis, lack of a functional methionine synthase did not cause a requirement for adenine. The introduction of genes from Sac. cerevisiae constituting the cystathionine pathway (CYS4 and CYS3) into Sch. pombe Δmet26 cells restored growth in the absence of adenine. HPLC analysis showed that total homocysteine content in Δmet26 cells was higher than in other methionine auxotrophs and that introduction of the Sac. cerevisiae cystathionine pathway decreased total homocysteine levels. These data demonstrate that accumulation of homocysteine causes a defect in purine biosynthesis in the met26 mutant.
AB - Methionine synthase (EC2.1.1.14) catalyses the final step in methionine synthesis, i.e. methylation of homocysteine. A search of the Schizosaccharomyces pombe genomic database revealed a gene designated SPAC9.09, encoding a protein with significant homology to methionine synthase. Disruption of SPAC9.09 caused methionine auxotrophy, and thus the gene was identified as a methionine synthase and designated met26. The met26 mutant was found to exhibit a remarkable growth defect in the absence of adenine even in medium supplemented with methionine. This phenotype was not observed in other methionine auxotrophs. In the budding yeast Saccharomyces cerevisiae, which has been reported to utilize homocysteine in cysteine synthesis, lack of a functional methionine synthase did not cause a requirement for adenine. The introduction of genes from Sac. cerevisiae constituting the cystathionine pathway (CYS4 and CYS3) into Sch. pombe Δmet26 cells restored growth in the absence of adenine. HPLC analysis showed that total homocysteine content in Δmet26 cells was higher than in other methionine auxotrophs and that introduction of the Sac. cerevisiae cystathionine pathway decreased total homocysteine levels. These data demonstrate that accumulation of homocysteine causes a defect in purine biosynthesis in the met26 mutant.
UR - http://www.scopus.com/inward/record.url?scp=32244441128&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=32244441128&partnerID=8YFLogxK
U2 - 10.1099/mic.0.28398-0
DO - 10.1099/mic.0.28398-0
M3 - Article
C2 - 16436428
AN - SCOPUS:32244441128
VL - 152
SP - 397
EP - 404
JO - Microbiology
JF - Microbiology
SN - 1350-0872
IS - 2
ER -