Homolog of tocopherol C methyltransferases catalyzes N methylation in anticancer alkaloid biosynthesis

David K. Liscombe, Aimee R. Usera, Sarah E. O'Connor

Research output: Contribution to journalArticlepeer-review

61 Citations (Scopus)

Abstract

Madagascar periwinkle (Catharanthus roseus) is the sole source of the anticancer drugs vinblastine and vincristine, bisindole alkaloids derived from the dimerization of the terpenoid indole alkaloids vindoline and catharanthine. Full elucidation of the biosynthetic pathways of these compounds is a prerequisite for metabolic engineering efforts that will improve production of these costly molecules. However, despite the medical and commercial importance of these natural products, the biosynthetic pathways remain poorly understood. Here we report the identification and characterization of a C. roseus cDNA encoding an S-adenosyl-L-methionine-dependent N methyltransferase that catalyzes a nitrogen methylation involved in vindoline biosynthesis. Recombinant enzyme produced in Escherichia coli is highly substrate specific, displaying a strict requirement for a 2,3-dihydro bond in the aspidosperma skeleton. The corresponding gene transcript is induced in methyl jasmonate-elicited seedlings, along with the other known vindoline biosynthetic transcripts. Intriguingly, this unique N methyltransferase is most similar at the amino acid level to the plastidic ?-tocopherol C methyltransferases of vitamin E biosynthesis, suggesting an evolutionary link between these two functionally disparate methyltransferases.
Original languageEnglish
Pages (from-to)18793-18798
Number of pages6
JournalProceedings of the National Academy of Sciences
Volume107
Issue number44
DOIs
Publication statusPublished - 2010

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