EPR DEMONSTRATION OF IRON NITROSYL COMPLEX-FORMATION BY CYTOTOXIC ACTIVATED MACROPHAGES
EPR DEMONSTRATION OF IRON NITROSYL COMPLEX-FORMATION BY CYTOTOXIC ACTIVATED MACROPHAGES
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DOI：
10.1073/pnas.87.3.1223
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发表时间：
1990-02-01
影响因子：
11.1
通讯作者：
HIBBS, JB
中科院分区：
文献类型：
--
作者：
LANCASTER, JR;HIBBS, JB
活化的巨噬细胞细胞毒性的特征是细胞内铁的损失和某些酶的抑制，这些酶具有催化活性的非血红素铁与硫配位。这一现象涉及L精氨酸末端的胍基氮原子之一的氧化，从而产生瓜氨酸和无机氮氧化物(亚硝酸根、硝酸根和一氧化氮)。我们在这里报告了对细胞毒性激活的巨噬细胞(CAM)效应细胞进行的电子顺磁共振波谱研究的结果，这些效应细胞表现出与其靶点相同的代谢抑制模式。对感染牛分枝杆菌(卡介苗)小鼠的活化巨噬细胞在含有脂多糖和L精氨酸的培养液中进行培养，发现在g=2.039处有一个轴向信号，这与先前报道的一氧化氮(NO)破坏铁-硫中心形成的铁-亚硝基复合体相似。通过添加NG-单甲基-L-精氨酸(末端的胍基氮上的甲基)来抑制L-精氨酸依赖的途径，可以抑制亚硝酸盐、硝酸盐、瓜氨酸和g=2.039信号的产生。将L-精氨酸处理的细胞信号的超精细结构与天然丰度为N14原子的末端胍基氮原子或N15原子标记的末端胍基氮原子进行比较，结果表明该顺磁性物种中的亚硝基来自这两个原子中的一个。这些结果表明，CAM含铁酶功能的丧失是由于L-精氨酸末端的胍基氮原子氧化合成一氧化氮而形成亚铁-亚硝基复合体的结果。
Activated macrophage cytotoxicity is characterized by loss of intracellular iron and inhibition of certain enzymes that have catalytically active nonheme-iron coordinated to sulfur. This phenomenon involves the oxidation of one of the terminal guanidino nitrogen atoms of L-arginine, which results in the production of citrulline and inorganic nitrogen oxides (NO2-, NO3-, and NO). We report here the results of an electron paramagnetic resonance spectroscopic study performed on cytotoxic activated macrophage (CAM) effector cells, which develop the same pattern of metabolic inhibition as their targets. Examination of activated macrophages from mice infected with Mycobacterium bovis (strain bacillus Calmette-Guerin) that were cultured in medium with lipopolysaccharide and L-arginine showed the presence of an axial signal at g = 2.039, which is similar to previously described iron-nitrosyl coomplexes formed from the destruction of iron-sulfur centers by nitric oxide (NO). Inhibition of the L-arginine-dependent pathway by addition of NG-monomethyl-L-arginine (methyl group on a terminal guanidino nitrogen) inhibits the production of nitrite, nitrate, citrulline, and the g = 2.039 signal. Comparison of the hyperfine structure of the signal from cells treated with L-arginine with terminal guanidino nitrogen atoms of natural abundance N14 atoms or labeled with N15 atoms showed that the nitrosyl group in this paramagnetic species arises from one of these two atoms. These results show that loss of iron-containing enzyme function in CAM is a result of the formation of iron-nitrosyl complexes induced by the synthesis of nitric oxide from the oxidation of a terminal guanidino nitrogen atom of L-arginine.