Dissecting the Mechanism of the Nonheme Iron Endoperoxidase FtmOx1 Using Substrate Analogues.
Dissecting the Mechanism of the Nonheme Iron Endoperoxidase FtmOx1 Using Substrate Analogues.
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DOI：
10.1021/jacsau.2c00248
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发表时间：
2022-07-25
期刊：
影响因子：
8
通讯作者：
Liu, Pinghua
中科院分区：
文献类型：
--
作者：
Zhu, Guoliang;Yan, Wupeng;Wang, Xinye;Cheng, Ronghai;Naowarojna, Nathchar;Wang, Kun;Wang, Jun;Song, Heng;Wang, Yuyang;Liu, Hairong;Xia, Xuekui;Costello, Catherine E;Liu, Xueting;Zhang, Lixin;Liu, Pinghua
FtmOx 1是一种非血红素铁（NHFe）内过氧化物酶，在体外条件下催化三种不同的反应，内过氧化，醇脱氢和脱烷基化;多样性使其机制研究复杂化。在这项研究中，我们使用两种底物类似物将FtmOx 1催化的反应简化为脱烷基化或醇脱氢反应，用于结构-功能关系分析，以解决两个关键的FtmOx 1机理问题：（1）提出的COX样模型中的Y224翻转与CarC样机制模型中提出的α-酮戊二酸（αKG）旋转，以及（2）Y224自由基的参与（COX-样模型）或Y 68自由基（CarC-样模型）。当13-氧代烟曲霉素B（7）用作底物时，FtmOx 1-催化从内过氧化反应变为羟基化反应并导致脱烷基化。此外，与类COX模型预测中的脱烷基化副反应一致，FtmOx 1·CoII·αKG·7三元复合物的X射线结构显示Y224翻转为相对于FtmOx 1·FeII·αKG二元复合物的替代构象。Verruculogen（2）被用作第二种底物类似物来研究醇脱氢反应，以检查Y224自由基或Y 68自由基在FtmOx 1-催化中的参与，并且再次，Verruculogen反应的结果更符合类COX模型。
FtmOx1 is a nonheme iron (NHFe) endoperoxidase, catalyzing three disparate reactions, endoperoxidation, alcohol dehydrogenation, and dealkylation, under in vitro conditions; the diversity complicates its mechanistic studies. In this study, we use two substrate analogues to simplify the FtmOx1-catalyzed reaction to either a dealkylation or an alcohol dehydrogenation reaction for structure–function relationship analysis to address two key FtmOx1 mechanistic questions: (1) Y224 flipping in the proposed COX-like model vs α-ketoglutarate (αKG) rotation proposed in the CarC-like mechanistic model and (2) the involvement of a Y224 radical (COX-like model) or a Y68 radical (CarC-like model) in FtmOx1-catalysis. When 13-oxo-fumitremorgin B (7) is used as the substrate, FtmOx1-catalysis changes from the endoperoxidation to a hydroxylation reaction and leads to dealkylation. In addition, consistent with the dealkylation side-reaction in the COX-like model prediction, the X-ray structure of the FtmOx1•CoII•αKG•7 ternary complex reveals a flip of Y224 to an alternative conformation relative to the FtmOx1•FeII•αKG binary complex. Verruculogen (2) was used as a second substrate analogue to study the alcohol dehydrogenation reaction to examine the involvement of the Y224 radical or Y68 radical in FtmOx1-catalysis, and again, the results from the verruculogen reaction are more consistent with the COX-like model.