中国科学院微生物研究所陈义华团队报道了，细胞色素P450酶选择性合成2-氧吲哚或3-羟基六氢吡咯-[2,3-b]吲哚环肽。相关研究成果于2025年1月16日发表于国际一流学术期刊《美国化学会杂志》上。

2-羟吲哚和三环3a-羟基六氢吡咯并[2,3-b]吲哚（HO-HPI）的结构基团是重要的药效团。化学合成含有2-羟吲哚或HO-HPI部分的复杂生物碱，尤其是后者，一直是一个长期存在的挑战。

该文中，研究人员将P450酶AfnD及其同源蛋白HmtT、ClpD、KtzM和LtzR表征为环肽2-羟吲哚和HO-HPI单加氧酶（cpOPMO），它们可以以pH依赖的方式将2-羟吲哚或HO-HPI部分引入含色氨酸的环肽中。研究人员提出了五种cpOPMOs的通用催化机制，其中两个保守的残基Asp和Ser（Thr代表LtzR）被提出以发散性打开环氧化物中间体，从而形成2-羟吲哚或HO-HPI部分。

在此基础上，研究人员构建了10个cpOPMOs的Asp或Ser/Thr突变体，它们可以在适当的反应条件下选择性地合成具有HO-HPI或2-吲哚结构的环肽。所有10个cpOPMOs突变体都表现出高底物混杂性，通常与结构上与其天然底物相似的环肽表现良好。

总的来说，该工作发现了一组有趣的P450酶，即cpOPMOs，并为选择性合成含HO-HPI-或2-吲哚的环肽提供了一个强大的酶工具包。

附：英文原文

Title: Selective Synthesis of Cyclopeptides with a 2-Oxindole or 3a-Hydroxy-hexahydropyrrolo-[2,3-b]indole Structure by Cytochrome P450 Enzymes

Author: Chao Li, Junying Ma, Lu Guo, Chao Xu, Zijian Zhong, Pengwei Li, Yue Tang, Wenzhao Wang, Defeng Li, Tao Ye, Zhengyan Guo, Yihua Chen

Issue&Volume: January 16, 2025

Abstract: The structural groups of 2-oxindole and tricyclic 3a-hydroxy-hexahydropyrrolo-[2,3-b]indole (HO-HPI) are important pharmacophores. Chemical synthesis of complex alkaloids containing a 2-oxindole or HO-HPI moiety, especially the latter one, has been a long-standing challenge. Herein, we characterized the P450 enzyme AfnD, and its homologue proteins, HmtT, ClpD, KtzM, and LtzR, as cyclopeptide 2-oxindole and HO-HPI monooxygenases (cpOPMOs) that could introduce a 2-oxindole or HO-HPI moiety into the tryptophan-containing cyclopeptides in a pH-dependent manner. A universal catalytic mechanism was proposed for the five cpOPMOs, in which two conserved residues, Asp and Ser (Thr for LtzR), were proposed to divergently open the epoxide intermediates, thereby forming a 2-oxindole or HO-HPI moiety. Based on this, we constructed ten Asp or Ser/Thr mutants of cpOPMOs, which could synthesize cyclopeptides with an HO-HPI or 2-oxindole structure, selectively, under appropriate reaction conditions. All of the ten cpOPMO mutants exhibited high substrate promiscuities and usually performed well with cyclopeptides that are structurally similar to their native substrates. Overall, our work discovers a group of intriguing P450 enzymes, the cpOPMOs, and provides a powerful enzymatic toolkit for the selective synthesis of HO-HPI- or 2-oxindole-containing cyclopeptides.

DOI: 10.1021/jacs.4c13535

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c13535