Structures, Spectroscopic Properties, and Dioxygen Reactivity of 5- and 6-Coordinate Nonheme Iron(II) Complexes: A Combined Enzyme/Model Study of Thiol Dioxygenases.
Structures, Spectroscopic Properties, and Dioxygen Reactivity of 5- and 6-Coordinate Nonheme Iron(II) Complexes: A Combined Enzyme/Model Study of Thiol Dioxygenases.
复制标题
DOI：
10.1021/jacs.8b08349
复制
发表时间：
2018-11-07
影响因子：
15
通讯作者：
Goldberg DP
中科院分区：
文献类型：
--
作者：
Gordon JB;McGale JP;Prendergast JR;Shirani-Sarmazeh Z;Siegler MA;Jameson GNL;Goldberg DP
描述了作为硫醇双加氧酶模型的四种新 FeII(N4S(硫醇盐)) 配合物的合成。它们由中性三齿配体三氮杂环壬烷 (R3TACN; R = Me, iPr) 和 2-氨基苯硫醇 (abtx; X = H, CF3) 的衍生物组成，后者是半胱氨酸双加氧酶 (CDO) 的非天然底物。这些配合物的配位数取决于 TACN 衍生物的身份，为 FeII(Me3TACN)(abtx)(OTf) 提供 6 配位（6 配位）配合物（1：X = H；2：X = CF3），为 [FeII（iPr3TACN）（abtx）]（OTf）提供 5 配位（5 配位）配合物（3：X = H；4：X = CF3）。通过 UV-vis、1H/19F NMR 和穆斯堡尔光谱检查配合物 1 – 4，并采用密度泛函理论 (DFT) 计算来支持数据。穆斯堡尔光谱显示，6 配位 1 – 2 和 5 配位 3 – 4 表现出不同的光谱，并将这些数据与半胱氨酸结合的 CDO 的数据进行比较，有助于阐明半胱氨酸结合的 FeII 活性位点的配位环境。 1或2与O2在-95°C下反应导致abt配体的S-氧化，在2的情况下，获得了一种罕见的二（亚磺基）桥络合物[Fe2III(μ-O)(O2S(NH2)C6H3CF3)2](OTf)2 (5)。使用 abt 底物对 CDO 变体 C93G 进行平行酶促研究，结果表明与 O2 的反应导致二硫键形成，而不是 S-氧化。组合模型和酶研究表明，硫醇双加氧酶可以通过 6 配位 FeII 中心进行操作，这与公认的非血红素铁双加氧酶机制相反，并且与 Fe 的适当底物螯合似乎对于 S-氧化至关重要。
The synthesis of four new FeII(N4S(thiolate)) complexes as models of the thiol dioxygenases are described. They are composed of derivatives of the neutral, tridentate ligand triazacyclononane (R3TACN; R = Me, iPr) and 2-aminobenzenethiolate (abtx; X = H, CF3), a non-native substrate for cysteine dioxygenase (CDO). The coordination number of these complexes depends on the identity of the TACN derivative, giving 6-coordinate (6-coord) complexes for FeII(Me3TACN)(abtx)(OTf) (1: X = H; 2: X = CF3), and 5-coordinate (5-coord) complexes for [FeII(iPr3TACN)(abtx)](OTf) (3: X = H; 4: X = CF3). Complexes 1 – 4 were examined by UV-vis, 1H/19F NMR, and Mössbauer spectroscopies, and density functional theory (DFT) calculations were employed to support the data. Mössbauer spectroscopy reveals that the 6-coord 1 – 2 and 5-coord 3 – 4 exhibit distinct spectra, and these data are compared with that for cysteine-bound CDO, helping to clarify the coordination environment of the cys-bound FeII active site. Reaction of 1 or 2 with O2 at −95 °C leads to S-oxygenation of the abt ligand, and in the case of 2, a rare di(sulfinato)-bridged complex, [Fe2III(µ-O)(O2S(NH2)C6H3CF3)2](OTf)2 (5), was obtained. Parallel enzymatic studies on the CDO variant C93G were carried out with the abt substrate, and show that reaction with O2 leads to disulfide formation, as opposed to S-oxygenation. The combined model and enzyme studies show that the thiol dioxygenases can operate via a 6-coord FeII center, in contrast to the accepted mechanism for nonheme iron dioxygenases, and that proper substrate chelation to Fe appears to be critical for S-oxygenation..
登录
查看更多内容
影响因子：
2.9
作者：
Diebold, Adrienne R.;Neidig, Michael L.;Moran, Graham R.;Straganz, Grit D.;Solomon, Edward I.
通讯作者：
Solomon, Edward I.
影响因子：
4.6
作者：
Das, Uttam K.;Daifuku, Stephanie L.;Baker, R. Tom
通讯作者：
Baker, R. Tom
影响因子：
15
作者：
Biswas, Achintesh N.;Puri, Mayank;Que, Lawrence, Jr.
通讯作者：
Que, Lawrence, Jr.
影响因子：
15
作者：
Aluri, Swathi;de Visser, Sam P.
通讯作者：
de Visser, Sam P.
DOI：
10.1039/dt9840001349
发表时间：
1984-01-01
期刊：
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
影响因子：
--
作者：
ADDISON, AW;RAO, TN;VERSCHOOR, GC
通讯作者：
VERSCHOOR, GC