Molecular genetics of acetate-derived naphtylisoquinoline alkaloid biosynthesis in the liane Triphyophyllum peltatum

藤本植物 Triphyophyllum peltatum 乙酸酯衍生的萘基异喹啉生物碱生物合成的分子遗传学

• 批准号: 5404609
• 负责人: Professorin Dr. Toni M. Kutchan
• 金额: --
• 依托单位: Donald Danforth Plant Science Center
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2005-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5404609?language=en
• 关键词: Molecular; genetics; acetate; derived; naphtylisoquinoline

In members of the plant families Berberidaceae, Papaveraceae and Ranunculaceae, tetrahydrobenzylisoquinoline-derived alkaloids originate from two molecules of the primary amino acid L-tyrosine. The nitrogen atom found in the isoquinoline moiety is provided by one of the L-tyrosine molecules. However, the carbon skeleton of isoquinoline alkaloids found in species of the Ancistrocladaceae and Dioncophyllaceae originates from acetate rather than from L-tyrosine. This curious alternative evolutionary origin of isoquinoline alkaloids can best be understood by a sequence analysis and comparison of the genes encoding the biosynthetic enzymes. Naphthylisoquinoline alkaloids in the liane Triphyophyllum peltatum (Doncophyllaceae) are derived form acetate. A putative polyketide synthase(s) should catalyze the formation of the naphthyl- and isoquinoline moietes. During ring formation, a nitrogen atom of unknown origin must be inserted into the folding polyketide chain in order to form the heterocycle. It is aimed in this project to establish by enzymological and molecular genetic methods whether the T. peltatum polyketide synthase is related to bacterial type I-, II- or to plant type III PKSs and to establish the immediate origin of the nitrogen atom. An additional goal is to identify the nature of the enzyme that catalyzes the C-C phenol coupling reaction.

在小檗科、罂粟科和毛茛科的植物中，四氢苄基异喹啉衍生的生物碱来源于两个分子的初级氨基酸L-酪氨酸。在异喹啉部分中发现的氮原子由L-酪氨酸分子之一提供。然而，在钩枝科和薯蓣科物种中发现的异喹啉生物碱的碳骨架源自乙酸盐而不是L-酪氨酸。异喹啉生物碱的这种奇怪的替代进化起源可以通过编码生物合成酶的基因的序列分析和比较来最好地理解。盾叶三叶草（Triphyophyllum peltatum）是一种藤本植物，其萘异喹啉生物碱是由乙酸乙酯衍生而来.推定的聚酮合酶应该催化萘基和异喹啉部分的形成。在环形成期间，未知来源的氮原子必须插入折叠聚酮化合物链中以形成杂环。本研究的目的是通过酶学和分子遗传学的方法来确定T。盾形藻聚酮合酶与细菌I型、II型或植物III型PKS相关，并建立了氮原子的直接来源。另一个目标是确定催化C-C苯酚偶联反应的酶的性质。