Unveiling the Bacterial Sesquiterpenome of Streptomyces sp. CBMAI 2042 Discloses Cyclases with Versatile Performances

Terpenes are the most abundant class of natural product that exist in nature. They possess a myriad of industrial applications including pharmaceutical, perfumery and flavors, bulk chemicals, and fuel. Intriguingly, until today, the vast majority of characterized terpenoids have been isolated from plants and fungi, and only in recent years bacteria were found to generate a representative reservoir of terpenoids molecules. Mining Streptomyces sp. CBMAI 2042 genome data has revealed the presence of five terpene cyclase genes. Chemical analysis of mycelium extract of this bacteria strain has unveiled at least 28 volatile terpenes molecules, where three encoding sesquiterpene cyclase (STC) genes are apparently responsible for their biosynthesis. The cyclic products obtained by incubation of these three purified recombinant STCs with farnesyl diphosphate (FPP) were analyzed by gas chromatography-mass spectrometry (GC-MS) and identified using the Van den Dool and Kratz equation.

萜类（Terpenes）是自然界中分布最为广泛的一类天然产物，拥有众多工业应用场景，涵盖医药、香料香精、大宗化学品及燃料领域。值得注意的是，截至目前绝大多数已被表征的萜类化合物（terpenoids）均分离自植物与真菌，直至近年才发现细菌可产生具有代表性的萜类化合物储库。通过对链霉菌（Streptomyces sp.）CBMAI 2042的基因组数据进行挖掘，发现其携带5个萜类环化酶基因。对该菌株的菌丝体提取物进行化学分析后，鉴定出至少28种挥发性萜类分子，其中3个编码倍半萜环化酶（sesquiterpene cyclase, STC）的基因被认为负责这些分子的生物合成。将这3种纯化的重组倍半萜环化酶与法尼基焦磷酸（farnesyl diphosphate, FPP）共孵育后得到的环化产物，通过气相色谱-质谱联用仪（gas chromatography-mass spectrometry, GC-MS）进行分析，并采用Van den Dool与Kratz方程完成产物鉴定。