Three Arabidopsis genes encoding proteins with differential activities for cysteine synthase and β-cyanoalanine synthase

Yube Yamaguchi, Tatsuo Nakamura, Tomonobu Kusano, Hiroshi Sano

    Research output: Contribution to journalArticle

    62 Citations (Scopus)

    Abstract

    Three cDNA clones encoding putative cysteine synthases (O-acetylserine (thiol) lyase, EC 4.2.99.8) were isolated from Arabidopsis thaliana and designated AtcysC1, AtcysD1 and AtcysD2, respectively. Southern blot analyses suggested that the corresponding genes were present as a single copy, or at most two copies, in the A. thaliana genome. Escherichia coli complementation analyses confirmed that the cDNAs encode cysteine synthase and the corresponding proteins produced in E. coli clearly showed cysteine synthase activity. In addition, AtcysC1 protein showed β-cyanoalanine synthase (EC 4.4.1.9) activity, but the other two did not. Kinetic analysis suggests that AtcysC1 actually functions as β-cyanoalanine synthase rather than cysteine synthase in vivo. The mRNA accumulation of AtcysC1, AtcysD1 and AtcysD2 differed in various organs, but did not change markedly when A. thaliana seedlings were subjected to various stresses, including nutrient deprivation. In vivo targeting experiments indicated that AtcysD1 and AtcysD2 are cytoplasmic isozymes, and AtcysC1 is a mitochondrial isozyme.

    Original languageEnglish
    Pages (from-to)465-476
    Number of pages12
    JournalPlant and Cell Physiology
    Volume41
    Issue number4
    DOIs
    Publication statusPublished - 2000 Jan 1

    Keywords

    • Arabidopsis thaliana
    • Cysteine synthase
    • Pyridoxal 5'-phosphate
    • β-cyanoalanine synthase

    ASJC Scopus subject areas

    • Physiology
    • Plant Science
    • Cell Biology

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