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Engineering triterpene production in Saccharomyces cerevisiae –β‐amyrin synthase from Artemisia annua
Author(s) -
Kirby James,
Romanini Dante W.,
Paradise Eric M.,
Keasling Jay D.
Publication year - 2008
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2008.06343.x
Subject(s) - artemisia annua , triterpene , saccharomyces cerevisiae , chemistry , botany , biochemistry , biology , yeast , plasmodium falciparum , medicine , immunology , artemisinin , alternative medicine , pathology , malaria
Using a degenerate primer designed from triterpene synthase sequences, we have isolated a new gene from the medicinal plant Artemisia annua . The predicted protein is highly similar to β‐amyrin synthases (EC 5.4.99.–), sharing amino acid sequence identities of up to 86%. Expression of the gene, designated AaBAS , in Saccharomyces cerevisiae , followed by GC/MS analysis, confirmed the encoded enzyme as a β‐amyrin synthase. Through engineering the sterol pathway in S. cerevisiae , we explore strategies for increasing triterpene production, using AaBAS as a test case. By manipulation of two key enzymes in the pathway, 3‐hydroxy‐3‐methylglutaryl‐CoA reductase and lanosterol synthase, we have improved β‐amyrin production by 50%, achieving levels of 6 mg·L −1 culture. As we have observed a 12‐fold increase in squalene levels, it appears that this strain has the capacity for even higher β‐amyrin production. Options for further engineering efforts are explored.