Isolation, Expression, and Functional Characterization of Esterases in the Emetine Alkaloid Biosynthesis Pathway of Psychotria ipecacuanha
Dr. Brent Buckner, Faculty Mentor
Plants in the family Rubiaceae are known for their production of monoterpene isoquinoline alkaloids referred to as ipecac alkaloids. The genes responsible for a few crucial steps in the emetine biosynthesis pathway of Psychotria ipecacuana (Rubiaceae) remain undiscovered. The reaction yielding protoemetine is thought to be catalyzed by an esterase due to the involvement of polyneuridine aldehyde esterase (PNAE) in a similar step of the related monoterpenoid indole alkaloid biosynthetic pathway of Rauvolfia serpentina (Apocynaceae). Eight putative esterase genes were found in the Psychotria transcriptome. Potential Psychotria esterase Contig30390 was cloned, expressed, and purified. HPLC was performed for substrate and product analysis to assess Contig30390s ability to catalyze the putative esterase reaction from 6,7-O,O-dimethyldeacetylisoipecoside deglucosylated to protoemetine. Protoemetine was not produced at a detectable level. This research demonstrates that Contig30390 is likely not the gene encoding the enzyme responsible for the reaction producing protoemitine.
Keywords: psychotria, ipecac, alkaloid, rubiaceae, protoemetine, 6,7-O,O-dimethyldeacetylisoipecoside, PNAE, clone
Presentation Type: Oral Paper
Location: MG 1098