Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747, AG, Groningen, The Netherlands.
Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747, AG, Groningen, The Netherlands.
Chemistry. 2019 Oct 1;25(55):12698-12702. doi: 10.1002/chem.201902907. Epub 2019 Sep 9.
We report the late-stage chemical modification of ribosomally synthesized and post-translationally modified peptides (RIPPs) by Diels-Alder cycloadditions to naturally occurring dehydroalanines. The tail region of the thiopeptide thiostrepton could be modified selectively and efficiently under microwave heating and transition-metal-free conditions. The Diels-Alder adducts were isolated and the different site- and endo/exo isomers were identified by 1D/2D H NMR. Via efficient modification of the thiopeptide nosiheptide and the lanthipeptide nisin Z the generality of the method was established. Minimum inhibitory concentration (MIC) assays of the purified thiostrepton Diels-Alder products against thiostrepton-susceptible strains displayed high activities comparable to that of native thiostrepton. These Diels-Alder products were also subjected successfully to inverse-electron-demand Diels-Alder reactions with a variety of functionalized tetrazines, demonstrating the utility of this method for labeling of RiPPs.
我们报告了通过 Diels-Alder 环加成反应对核糖体合成和翻译后修饰的肽（RIPPs）进行后期化学修饰，该反应针对的是天然存在的脱氢丙氨酸。在微波加热和无过渡金属条件下，硫肽硫丝菌素的尾部区域可以选择性和有效地进行修饰。通过 1D/2D H NMR 鉴定了 Diels-Alder 加合物，并确定了不同的位和内/外异构体。通过对硫肽诺西肽和兰尼肽 nisin Z 的有效修饰，确立了该方法的通用性。对纯化的硫丝菌素 Diels-Alder 产物进行的最小抑菌浓度（MIC）测定显示，其对硫丝菌素敏感菌株的活性与天然硫丝菌素相当。这些 Diels-Alder 产物还成功地与各种功能化四嗪进行了逆电子需求 Diels-Alder 反应，证明了该方法在 RiPPs 标记中的实用性。
