Homocysteine accumulation causes a defect in purine biosynthesis: Further characterization of Schizosaccharomyces pombe methionine auxotrophs

Yasuko Fujita, Eiko Ukena, Haruyuki Iefuji, Yuko Giga-Hama, Kaoru Takegawa

研究成果: Contribution to journalArticle査読

20 被引用数 (Scopus)

抄録

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.

本文言語英語
ページ(範囲)397-404
ページ数8
ジャーナルMicrobiology
152
2
DOI
出版ステータス出版済み - 2 2006
外部発表はい

All Science Journal Classification (ASJC) codes

  • 微生物学

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