Computational Description of Alkylated Iron–Sulfur Organometallic Clusters
Computational Description of Alkylated Iron–Sulfur Organometallic Clusters
复制标题
烷基化铁硫有机金属簇的计算描述
DOI：
10.1021/jacs.3c03062
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发表时间：
2023
影响因子：
15
通讯作者：
Mosquera, Martín A.
中科院分区：
文献类型：
--
作者：
Jodts, Richard J.;Wittkop, M;Ho, Madeline B.;Broderick, William E.;Broderick, Joan B.;Hoffman, Brian M.;Mosquera, Martín A.
自由基S-腺苷甲硫氨酸（SAM）酶超家族在具有重要生物学意义的氢原子提取反应中发挥着广泛的作用。在这些酶中，与 [4Fe-4S]1+ 簇结合的 SAM 发生还原裂解，生成 5'-脱氧腺苷基自由基 (5'-dAdo•)，最终从底物中提取一个 H 原子。然而，压倒性的实验证据令人惊讶地揭示了一种具有 Fe-C5'-腺苷键的强制性有机金属中间体 Ω，其特性是本理论研究的目标。我们报告了一种易于应用的破缺对称 DFT 的两种配置版本，表示为 2C-DFT，旨在准确描述与多金属铁硫簇结合的烷基的超精细耦合常数和 g 张量。该方法已得到验证，其结果与一系列模型配合物的多构型完整活性空间自洽场计算结果以及与晶体学特征配合物 M–CH3（具有 Fe–CH3 键的 [4Fe-4S] 簇）的电子核双共振/电子顺磁共振波谱研究的结果非常一致。 Ω 的光谱结果和 2C-DFT 计算之间同样出色的一致性证实了其作为有机金属络合物的身份，如最初提出的那样，[4Fe-4S]簇的 Fe 与脱氧腺苷基部分的 C5' 之间存在键。
The radicalS-adenosyl methionine (SAM) enzyme superfamily has widespread roles in hydrogen atom abstraction reactions of crucial biological importance. In these enzymes, reductive cleavage of SAM bound to a [4Fe-4S]1+cluster generates the 5′-deoxyadenosyl radical (5′-dAdo•) which ultimately abstracts an H atom from the substrate. However, overwhelming experimental evidence has surprisingly revealed an obligatory organometallic intermediate Ω exhibiting an Fe-C5′-adenosyl bond, whose properties are the target of this theoretical investigation. We report a readily applied, two-configuration version of broken symmetry DFT, denoted 2C-DFT, designed to allow the accurate description of the hyperfine coupling constants and g-tensors of an alkyl group bound to a multimetallic iron–sulfur cluster. This approach has been validated by the excellent agreement of its results both with those of multiconfigurational complete active space self-consistent field computations for a series of model complexes and with the results from electron nuclear double-resonance/electron paramagnetic resonance spectroscopic studies for the crystallographically characterized complex, M–CH3, a [4Fe-4S] cluster with a Fe–CH3bond. The likewise excellent agreement between spectroscopic results and 2C-DFT computations for Ω confirm its identity as an organometallic complex with a bond between an Fe of the [4Fe-4S] cluster and C5′ of the deoxyadenosyl moiety, as first proposed.