Department of Chemistry, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin 300072, China.
School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China.
J Am Chem Soc. 2024 Jul 24;146(29):19962-19973. doi: 10.1021/jacs.4c03499. Epub 2024 Jul 10.
Installing fluorine atoms onto natural products holds great promise for the generation of fluorinated molecules with improved or novel pharmacological properties. The enzymatic oxidative carbon-carbon coupling reaction represents a straightforward strategy for synthesizing biaryl architectures, but the exploration of this method for producing fluorine-substituted derivatives of natural products remains elusive. Here, in this study, we report the protein engineering of cytochrome P450 from (CYP121) for the construction of a series of new-to-nature fluorine-substituted Mycocyclosin derivatives. This protocol takes advantage of a "hybrid" chemoenzymatic procedure consisting of tyrosine phenol lyase-catalyzed fluorotyrosine preparation from commercially available fluorophenols, intermolecular chemical condensation to give cyclodityrosines, and an engineered CYP121-catalyzed intramolecular biphenol coupling reaction to complete the strained macrocyclic structure. Computational mechanistic studies reveal that CYP121 employs Cpd I to abstract a hydrogen atom from the proximal phenolic hydroxyl group of the substrate to trigger the reaction. Then, conformational change makes the two phenolic hydroxyl groups close enough to undergo intramolecular hydrogen atom transfer with the assistance of a pocket water molecule. The final diradical coupling process completes the intramolecular C-C bond formation. The efficiency of the biaryl coupling reaction was found to be influenced by various fluorine substitutions, primarily due to the presence of distinct binding conformations.
在天然产物上引入氟原子，为生成具有改善或新颖药理学性质的氟化分子提供了巨大的可能性。酶促氧化碳-碳偶联反应是合成联苯结构的一种直接策略，但对于利用这种方法来合成天然产物的氟取代衍生物的探索仍然难以捉摸。在本研究中，我们报告了细胞色素 P450 （CYP121）的蛋白质工程，用于构建一系列新型的氟取代 Mycocyclosin 衍生物。该方案利用了一种“混合”的化学酶促程序，包括酪氨酸酚裂解酶催化的从市售氟苯酚制备氟酪氨酸、分子间化学缩合得到环二酪氨酸、以及工程化的 CYP121 催化的分子内双酚偶联反应来完成紧张的大环结构。计算力学研究表明，CYP121 使用 Cpd I 从底物的临近酚羟基中提取一个氢原子来触发反应。然后，构象变化使两个酚羟基足够接近，在口袋水分子的协助下进行分子内氢原子转移。最后，二自由基偶联过程完成了分子内 C-C 键的形成。双芳基偶联反应的效率被发现受到各种氟取代的影响，主要是由于存在不同的结合构象。
