Chemical investigation of Streptomyces sp. KIB 015, an endophyte from the plant Panax notoginseng, led to the discovery of two novel labdane diterpenes, labdanmycins A (1) and B (2). In order to reveal the biosynthesis of labdanmycins, the genome of S. sp. KIB 015 was sequenced and a lab gene cluster encoding GGPP synthase, class II cyclase, class I cyclase, and cytochrome P450s was confirmed to be involved in labdanmycin biosynthesis by heterologous expression and gene inactivation experiments. Biogenetic precursor raimonol (3) was isolated from the gene labE inactivation mutant strain S. sp. KIB 015 ΔlabE, which suggested that P450 enzyme LabE is responsible for oxidizing the C-20 methyl group of 3 to an aldehyde or carbonyl group to afford 1 and 2. Additional two new labdane diterpenes (4 and 5) were also isolated from the mutant S. sp. KIB 015 ΔlabE. The chemical structures of 1–5 were elucidated on the basis of extensive NMR and MS spectroscopic analyses.

中文翻译：

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拉丹霉素的分离和生物合成：来自内生链霉菌的四种新的拉丹烷二萜†

链霉菌属的化学研究。KIB 015是三七植物的内生菌，导致发现了两种新型的拉丹烷二萜，拉丹霉素A（1）和B（2）。为了揭示labdanmycins的生物合成，基因组S. SP。对KIB 015进行了测序，并通过异源表达和基因灭活实验，证实了编码GGPP合酶，II类环化酶，I类环化酶和细胞色素P450的实验室基因簇参与了拉丹霉素的生物合成。从LabE灭活突变菌株S. sp。分离出生物遗传前体雷莫诺（3）。KIB 015Δ拉贝，这表明P450酶LABE负责的C-20甲基基团氧化3成醛或羰基，得到1和2。还从突变体S. sp。分离了另外两个新的拉丹烷二萜（4和5）。KIB 015ΔlabE。在广泛的NMR和MS光谱分析的基础上阐明了1–5的化学结构。