An isoform-specific pivot modulates the electron transfer between the flavin mononucleotide and heme centers in inducible nitric oxide synthase.
An isoform-specific pivot modulates the electron transfer between the flavin mononucleotide and heme centers in inducible nitric oxide synthase.
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DOI：
10.1007/s00775-020-01824-w
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发表时间：
2020-12
期刊：
影响因子：
--
通讯作者：
Feng C
中科院分区：
文献类型：
--
作者：
Zheng H;Li J;Feng C
黄素单核苷酸（FMN）和血红素中心之间的域间电子转移（IET）是一氧化氮合酶（NOS）酶的一个必要步骤。在人诱导型一氧化氮合酶（iNOS）的血红素结构域中靠近Leu406的一个异构体特异性关键区域被认为可介导FMN - 血红素结构域 - 结构域的排列[Sheng, Y.等人（2015年）《无机生物化学杂志》153卷，186 - 196页]。FMN - 血红素IET速率是域间FMN/血红素复合物形成的一个衡量指标。在这项工作中，通过一氧化碳光解并添加与关键区域相关的合成肽，直接测量了野生型（wt）人iNOS加氧酶/FMN（oxyFMN）构建体中的FMN - 血红素IET动力学，并与单独的野生型构建体进行了比较。iNOS HKL肽以剂量饱和的方式降低了IET速率，并且该肽中的单个L406→E突变消除了这种效应。观察到这些肽对野生型iNOS全酶的NO合成活性变化有类似趋势。这些结果，连同L406T和L406F突变型oxyFMN蛋白的动力学和建模结果，表明Leu406残基通过疏水相互作用调节FMN - 血红素IET。此外，在存在与等效关键血红素结构域位点相关的nNOS或eNOS衍生肽的情况下，分析了野生型iNOS oxyFMN蛋白的IET速率。这些结果共同表明，血红素结构域上的异构体特异性关键区域与保守的FMN结构域表面特异性相互作用，以促进NOS中FMN - 血红素IET的正确域间对接。
Interdomain electron transfer (IET) between the flavin mononucleotide (FMN) and heme centers is an obligatory step in nitric oxide synthase (NOS) enzymes. An isoform-specific pivotal region near Leu406 in the heme domain of human inducible NOS (iNOS) was proposed to mediate the FMN-heme domain-domain alignment [Sheng, Y. et al. (2015) J. Inorg. Biochem. 153, 186-196]. The FMN - heme IET rate is a measure of the interdomain FMN/heme complex formation. In this work, the FMN - heme IET kinetics in the wild type (wt) human iNOS oxygenase/FMN (oxyFMN) construct were directly measured by CO photolysis with added synthetic peptide related to the pivotal region, in comparison with the wt construct alone. The IET rates were decreased by the iNOS HKL peptide in a dose-saturable fashion, and the effect was abolished by a single L406→E mutation in the peptide. A similar trend in change of the NO synthesis activity of wt iNOS holoenzyme by the peptides was observed. These results, along with the kinetics and modelling results for the L406T and L406F mutant oxyFMN proteins, indicated that the Leu406 residue modulates the FMN - heme IET through hydrophobic interactions. Moreover, the IET rates were analyzed for the wt iNOS oxyFMN protein in the presence of nNOS or eNOS-derived peptide related to the equivalent pivotal heme domain site. These results together indicate that the isoform-specific pivotal region at the heme domain specifically interacts with the conserved FMN domain surface, to facilitate proper interdomain docking for the FMN - heme IET in NOS.
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影响因子：
3.5
作者：
Li W;Fan W;Elmore BO;Feng C
通讯作者：
Feng C
影响因子：
12.9
作者：
Hedison TM;Leferink NG;Hay S;Scrutton NS
通讯作者：
Scrutton NS
影响因子：
4.8
作者：
Garcin, ED;Bruns, CM;Getzoff, ED
通讯作者：
Getzoff, ED
影响因子：
15
作者：
Cho, Kyung-Bin;Derat, Etienne;Shaik, Sason
通讯作者：
Shaik, Sason
DOI：
10.1021/acs.jpca.5b08414
发表时间：
2015-11-12
期刊：
The journal of physical chemistry. A
影响因子：
--
作者：
Astashkin AV;Feng C
通讯作者：
Feng C