In nature, the vast majority of sesquiterpenes are produced by type I mechanisms, and glycosylated sesquiterpenes are rare in actinobacteria. Streptomyces olindensis DAUFPE 5622 produces the sesquiterpenes olindenones A–G, a new class of rearranged drimane sesquiterpenes. Olindenones B–D are oxygenated derivatives of olindenone A, while olindenones E–G are analogs glycosylated with dideoxysugars. ¹³C-isotope labeling studies demonstrated olindenone A biosynthesis occurs via the methylerythritol phosphate (MEP) pathway and suggested the rearrangement is only partially concerted. Based on the structures, one potential mechanism of olindenone A formation proceeds by cyclization of the linear terpenoid precursor, likely occurring via a terpene cyclase-mediated type II mechanism whereby the terminal alkene of the precursor is protonated, triggering carbocation-driven cyclization followed by rearrangement. Diphosphate hydrolysis may occur either before or after cyclization. Although a biosynthetic route is proposed, the terpene cyclase gene responsible for producing olindenones currently remains unidentified.

中文翻译：

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来自林登链霉菌 DAUFPE 5622 的不寻常倍半萜

在自然界中，绝大多数倍半萜是通过I型机制产生的，糖基化倍半萜在放线菌中很少见。Streptomyces olindensis DAUFPE 5622 产生倍半萜 olindenones A–G，这是一类新的重排二甲亚胺倍半萜。林烯酮 B–D 是林烯酮 A 的氧化衍生物，而林烯酮 E–G 是双脱氧糖糖基化的类似物。¹³ C-同位素标记研究表明，奥林登酮 A 的生物合成是通过甲基赤藓糖醇磷酸 (MEP) 途径发生的，并表明重排仅部分一致。根据这些结构， olindenone A 形成的一种潜在机制是通过线性萜类前体的环化进行的，可能通过萜烯环化酶介导的 II 型机制发生，其中前体的末端烯烃被质子化，触发碳正离子驱动的环化，然后重排。二磷酸酯水解可在环化之前或之后发生。尽管提出了生物合成途径，但负责产生林烯酮的萜烯环化酶基因目前仍未确定。