Department of Chemistry, Irving K. Barber Faculty of Science, University of British Columbia 3247 University Way, Kelowna, BC V1V 1V7, Canada.
Department of Natural Product Biosynthesis, Max Planck Institute for Chemical Ecology Hans-Knöll-Straße 8, 07745 Jena, Germany.
ACS Chem Biol. 2020 Jul 17;15(7):1780-1787. doi: 10.1021/acschembio.0c00220. Epub 2020 Jun 11.
Iridoids are plant-derived terpenoids with a rich array of bioactivities. The key step in iridoid skeleton formation is the reduction of 8-oxogeranial by certain members of the progesterone 5β-reductase/iridoid synthase (PRISE) family of short-chain alcohol dehydrogenases. Other members of the PRISE family have previously been implicated in the biosynthesis of the triterpenoid class of cardenolides, which requires the reduction of progesterone. Here, we explore the occurrence and activity of PRISE across major lineages of plants. We observed trace activities toward either 8-oxogeranial or progesterone in all PRISEs, including those from nonseed plants and green algae. Phylogenetic analysis, coupled with enzymatic assays, show that these activities appear to have become specialized in specific angiosperm lineages. This broad analysis of the PRISE family provides insight into how these enzymes evolved in plants and also suggests that iridoid synthase activity is an ancestral trait in all land plants, which might have contributed to the rise of iridoid metabolites.
环烯醚萜类是一类具有丰富生物活性的植物衍生萜类化合物。环烯醚萜骨架形成的关键步骤是某些孕酮 5β-还原酶/环烯醚萜合酶（PRISE）家族的短链醇脱氢酶将 8-氧格尔醛还原。PRISE 家族的其他成员先前被牵连到三萜类强心苷的生物合成中，这需要孕酮的还原。在这里，我们探索了 PRISE 在植物主要谱系中的发生和活性。我们观察到所有 PRISE 都有痕量的 8-氧格尔醛或孕酮活性，包括非种子植物和绿藻中的 PRISE。系统发育分析结合酶分析表明，这些活性似乎在特定的被子植物谱系中专门化。对 PRISE 家族的广泛分析提供了对这些酶在植物中进化的深入了解，并表明环烯醚萜合酶活性是所有陆地植物的祖先特征，这可能促成了环烯醚萜类代谢物的出现。
