The resinous portions of Aquilaria plants, called agarwood, have been used as medicines and incenses. Agarwood contains a great variety of sesquiterpenes, and a study using cultured cells of Aquilaria showed the production of sesquiterpenes (α-guaiene, α-humulene, and δ-guaiene) to be induced by treatment with methyl jasmonate (MJ). In this study, the accumulation and production of sesquiterpenes were quantified. The amounts accumulated and produced reached a maximum at 12 h, and the most abundant product was α-humulene at 6 h and δ-guaiene after 12 h. However, a headspace analysis of the cells revealed that α-humulene is likely to be volatilized; so overall, the most abundant sesquiterpene in the cells was δ-guaiene. A cDNA library from RNA isolated from MJ-treated cells was screened using PCR methodologies to isolate five clones with very similar amino acid sequences. These clones were expressed in Escherichia coli, and enzymatic reactions using farnesyl pyrophosphate revealed that three of the clones yielded the same compounds as extracted from MJ-treated cells, the major product being δ-guaiene. These genes and their encoded enzymes are the first sesquiterpene synthases yielding guaiane-type sesquiterpenes as their major products to be reported. Expression of a fourth terpene synthase gene in bacteria resulted in the accumulation of the protein in insoluble forms. Site-directed mutagenesis of the inactive clone and three-dimensional homology modeling suggested that the structure of the N-terminal domain was important in facilitating proper folding of the protein to form a catalytically active structure.

中文翻译：

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沉香培养细胞中δ-愈创木酚合酶的表征，负责形成沉香中的倍半萜。

沉香植物的树脂部分，称为沉香，已被用作药物和熏香。沉香含有多种倍半萜，一项使用沉香培养细胞的研究表明，用茉莉酸甲酯 (MJ) 处理可诱导倍半萜（α-愈创木烯、α-葎草烯和 δ-愈创木烯）的产生。在这项研究中，对倍半萜烯的积累和生产进行了量化。积累和产生的量在 12 小时达到最大值，最丰富的产物是 6 小时的 α-葎草烯和 12 小时后的 δ-愈创木烯。然而，对细胞的顶空分析表明，α-葎烯可能会挥发；所以总的来说，细胞中最丰富的倍半萜是δ-愈创木。使用 PCR 方法筛选来自 MJ 处理细胞的 RNA 的 cDNA 文库，以分离具有非常相似的氨基酸序列的五个克隆。这些克隆在大肠杆菌中表达，使用焦磷酸法呢酯的酶促反应表明，其中三个克隆产生了与从 MJ 处理的细胞中提取的相同化合物，主要产物是 δ-愈创木。这些基因及其编码的酶是第一个产生愈创木酚型倍半萜烯作为其主要产物的倍半萜烯合酶。第四种萜烯合酶基因在细菌中的表达导致蛋白质以不溶性形式积累。