Spectroscopic and theoretical description of the electronic structure of the S = 3/2 nitrosyl complex of non-heme iron enzymes
Spectroscopic and theoretical description of the electronic structure of the S = 3/2 nitrosyl complex of non-heme iron enzymes
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非血红素铁酶 S = 3/2 亚硝酰复合物电子结构的光谱和理论描述
DOI：
10.1021/ja00049a062
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发表时间：
1992
影响因子：
15
通讯作者：
E. Solomon
中科院分区：
文献类型：
--
作者：
Yan Zhang;M. Pavlosky;C. A. Brown;Tami E. Westre;B. Hedman;K. Hodgson;E. Solomon
非血红素铁中心存在于大量参与氧结合和活化的酶的催化活性部位。大豆脂肪氧合酶(SBL)是这类酶中的一员，它催化1，4-不饱和脂肪与氧气反应生成过氧化氢产物。酶的亚硝基络合物是参与催化的可能的氧气中间体的可逆类似物。Sbl-NO和其他非血红素铁酶亚硝基络合物(式为(FeNO){sup7})表现出不寻常的S={sup3}/{sub2}{sub3}EPR信号，在(FeNO){sup7}模型络合物中也观察到了这种信号。对这些配合物的成键描述有很多，包括[Fe{sup+}d{sup 7}(S=3/2)-no{sup+}(S=O)]，[Fe{sup 2+}d{sup 6}(S=2)-no{sup 0}(S=1/2)]]反铁磁耦合，[Fe{sup 3+}d{sup 5}(S=1/2)-no{sup{负}}(S=1)]铁磁耦合，和[Fe{sup 3+}d{sup 5}(S=3/2)-no{sup{负}}(S=0)]。为了将这些酶的NO衍生物用作与氧反应有关的电子分布的探针，需要清楚地了解S=3/2(FeNO){sup 7}单元的电子结构和相关的光谱特征。用光谱技术和理论方法研究了SbL-NO和两个S=3/2基态模型络合物FeEL-(NO)(N{sub3}){submore=2}，其中L=N，N{素数}，N{double_prime}-trimethyl-1，4，7-triazacyclononane和FeEDTA-NO。参考文献20，图2。
Non-heme iron centers are present in the catalytic active sites of a large number of enzymes which are involved in the binding and activation of dioxygen. A member of this class, soybean lipoxygenase (SBL), catalyzes the reaction of 1,4-unsaturated lipids with dioxygen to form a hydroperoxide product. Nitrosyl complexes of enzymes serve as reversible analogues of possible dioxygen intermediates involved in catalysis. SBL-NO and other non-heme ferrous enzyme nitrosyl complexes (formulated as (FeNO){sup 7}) exhibit an unusual S = {sup 3}/{sub 2}{sub 3}EPR signal, which is also observed in (FeNO){sup 7} model complexes. A wide range of bonding descriptions have appeared for these complexes, which include [Fe{sup +}d{sup 7}(S = 3/2)-NO{sup +}(S = O)], [Fe{sup 2+}d{sup 6}(S=2)-NO{sup 0}(S=1/2)] antiferromagnetically coupled, [Fe{sup 3+}d{sup 5}(S =1/2)-NO{sup {minus}}(S = 1)] ferromagnetically coupled, and [Fe{sup 3+}d{sup 5}(S = 3/2)-NO{sup {minus}}(S=0)]. In order for the NO derivative of these enzymes to be used as a probe of electron distribution related to dioxygen reactivity, a clear understanding of the electronic structure and associated spectral features of the S = 3/2 (FeNO){sup 7} unit is required. Spectroscopic techniques and theoretical methods have been used to study SBL-NO and two S = 3/2 ground-state model complexes, FeL-(NO)(N{sub 3}){submore » 2}, where L = N,N{prime},N{double_prime}-trimethyl-1,4,7-triazacyclononane and FeEDTA-NO. 20 refs., 2 figs.« less