Model of the MitoNEET [2Fe-2S] Cluster Shows Proton Coupled Electron Transfer.
Model of the MitoNEET [2Fe-2S] Cluster Shows Proton Coupled Electron Transfer.
复制标题
DOI：
10.1021/jacs.6b09180
复制
发表时间：
2017-01-18
影响因子：
15
通讯作者：
Meyer F
中科院分区：
文献类型：
--
作者：
Bergner M;Dechert S;Demeshko S;Kupper C;Mayer JM;Meyer F
MitoNEET 是一种外膜蛋白，其确切功能尚不清楚，尽管该蛋白在氧化还原和铁传感以及控制最大线粒体呼吸速率中的作用已被讨论。它被证明含有氧化还原活性和酸不稳定的[2Fe-2S}簇，该簇由一个组氨酸和三个半胱氨酸残基连接。在此，我们提出了第一个具有仿生 {SN/S2} 连接的合成类似物，其结构可以以其二铁形式 52− 进行结构表征。除了作为生物辅因子的高保真结构模型之外，该复合物还被证明可以在 {SN} 连接位点介导质子偶联电子转移 (PCET)，这表明该酶独特的 His 配体具有潜在的功能作用。建立了 mitoNEET 模型 52− 和相关均配 {SN/SN} 封端的 [2Fe-2S] 簇 42− 的完整 PCET 热力学平方方案，并通过两种复合物的双混合停流实验研究了 PCET 反应动力学。虽然 5H2− (230 ± 4 kJ mol−1) 的 N-H 键解离自由能 (BDFE) 以及与 TEMPO 反应的自由能 ΔG°PCET (−48.4 kJ mol−1) 与均配簇 4H2− (232 ± 4 kJ mol−1, −46.3 kJ mol−1) 的值非常相似，但发现后者的反应速度明显快于mitoNEET 模型（5H2− 的数据：k = 135 ± 27 M−1s−1，ΔH‡ = 17.6 ± 3.0 kJ mol−1，ΔS‡ = −143 ± 11 J mol−1 K−1，ΔG‡ = 59.8 kJ mol−1（293 K））。这些簇的 PCET 效率的比较强调了重组能量在此过程中的相关性。
MitoNEET is an outer membrane protein whose exact function remains unclear, though a role of this protein in redox and iron sensing as well as in controlling maximum mitochondrial respiratory rates has been discussed. It was shown to contain a redox active and acid labile [2Fe-2S} cluster which is ligated by one histidine and three cysteine residues. Herein we present the first synthetic analogue with biomimetic {SN/S2} ligation which could be structurally characterized in its diferric form, 52−. In addition to being a high fidelity structural model for the biological cofactor, the complex is shown to mediate proton coupled electron transfer (PCET) at the {SN} ligated site, pointing at a potential functional role of the enzyme’s unique His ligand. Full PCET thermodynamic square schemes for the mitoNEET model 52− and a related homoleptic {SN/SN} capped [2Fe-2S] cluster 42− are established, and kinetics of PCET reactivity are investigated by double-mixing stopped-flow experiments for both complexes. While the N-H bond dissociation free energy (BDFE) of 5H2− (230 ± 4 kJ mol−1) and the free energy ΔG°PCET for the reaction with TEMPO (−48.4 kJ mol−1) are very similar to values for the homoleptic cluster 4H2− (232 ± 4 kJ mol−1, −46.3 kJ mol−1) the latter is found to react significantly faster than the mitoNEET model (data for 5H2−: k = 135 ± 27 M−1s−1, ΔH‡ = 17.6 ± 3.0 kJ mol−1, ΔS‡ = −143 ± 11 J mol−1 K−1, ΔG‡ = 59.8 kJ mol−1 at 293 K). Comparison of the PCET efficiency of these clusters emphasizes the relevance of reorganization energy in this process.
登录
查看更多内容
影响因子：
4.3
作者：
Albers, Antonia;Bayer, Thomas;Meyer, Franc
通讯作者：
Meyer, Franc
影响因子：
16.6
作者：
Albers, Antonia;Demeshko, Serhiy;Meyer, Franc
通讯作者：
Meyer, Franc
影响因子：
3.5
作者：
Boxhammer, S.;Glaser, S.;Schmidt, Christian L.
通讯作者：
Schmidt, Christian L.
影响因子：
4.8
作者：
Golinelli-Cohen, Marie-Pierre;Lescop, Ewen;Bouton, Cecile
通讯作者：
Bouton, Cecile
DOI：
10.1039/dt9920002457
发表时间：
1992-08-21
期刊：
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
影响因子：
--
作者：
BEARDWOOD, P;GIBSON, JF
通讯作者：
GIBSON, JF