Cycloaddition reactions generate chemical complexity in a single step. Here we report the crystal structures of three homologous plant-derived cyclases involved in the biosynthesis of iboga and aspidosperma alkaloids. These enzymes act on the same substrate, named angryline, to generate three distinct scaffolds. Mutational analysis reveals how these highly similar enzymes control regio- and stereo-selectivity.

中文翻译：

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环加成在伊波加和扁豆生物碱生物合成中的结构基础

环加成反应在一个步骤中产生化学复杂性。在这里，我们报告了参与 iboga 和 aspidosperma 生物碱生物合成的三种同源植物衍生环化酶的晶体结构。这些酶作用于同一个底物，称为angerline，产生三种不同的支架。突变分析揭示了这些高度相似的酶如何控制区域和立体选择性。