Germacrene A synthase（GAS） catalyzes the biosynthesis of germacrene A, which is a key precursor for sesquiterpone lactones. Cloning of a novel full-length cDNA encoding GAS from the medicinal plant Crepidiastrum son...Germacrene A synthase（GAS） catalyzes the biosynthesis of germacrene A, which is a key precursor for sesquiterpone lactones. Cloning of a novel full-length cDNA encoding GAS from the medicinal plant Crepidiastrum sonchifolium（dosignated CsGAS） is reported in this study. The cDNA is 1837 bp long and contains a 1680-bp open reading frame encoding a 559 amino-acid protein. The functional expression of the cDNA in Escherichia coli, as an N-terminal thioredoxin fusion protein, with the pET32a vector yielding a recombinant enzyme. Sequence analysis was used to compare this enzyme with the mechanistically related epi-aristolochene synthase from tobacco, and the effect of possible involvement of a number of amino acids in sesquiterpone synthase on product specificity was also discussed.展开更多
文摘Germacrene A synthase（GAS） catalyzes the biosynthesis of germacrene A, which is a key precursor for sesquiterpone lactones. Cloning of a novel full-length cDNA encoding GAS from the medicinal plant Crepidiastrum sonchifolium（dosignated CsGAS） is reported in this study. The cDNA is 1837 bp long and contains a 1680-bp open reading frame encoding a 559 amino-acid protein. The functional expression of the cDNA in Escherichia coli, as an N-terminal thioredoxin fusion protein, with the pET32a vector yielding a recombinant enzyme. Sequence analysis was used to compare this enzyme with the mechanistically related epi-aristolochene synthase from tobacco, and the effect of possible involvement of a number of amino acids in sesquiterpone synthase on product specificity was also discussed.
