CNRS, UMR 8221, CEA/iBiTec-S/SB2SM, Bât. 532, CEA Saclay, 91191 Gif-sur-Yvette Cedex (France).
Chembiochem. 2013 Sep 23;14(14):1852-7. doi: 10.1002/cbic.201300233. Epub 2013 Aug 13.
Nitric oxide is produced in mammals by a class of enzymes called NO synthases (NOSs). It plays a central role in cellular signalling but also has deleterious effects, as it leads to the production of reactive oxygen and nitrogen species. NO forms a relatively stable adduct with ferrous haem proteins, which, in the case of NOS, is also a key catalytic intermediate. Despite extensive studies on the ferrous nitrosyl complex of other haem proteins (in particular myoglobin), little characterisation has been performed in the case of NOS. We report here a temperature-dependent EPR study of the ferrous nitrosyl complex of the inducible mammalian NOS and the bacterial NOS-like protein from Bacillus subtilis. The results show that the overall behaviours are similar to those observed for other haem proteins, but with distinct ratios between axial and rhombic forms in the case of the two NOS proteins. The distal environment appears to control the existence of the axial form and the evolution of the rhombic form.
一氧化氮是哺乳动物中一类被称为一氧化氮合酶（NOS）的酶产生的。它在细胞信号转导中起着核心作用，但也有有害的影响，因为它导致活性氧和氮物种的产生。一氧化氮与亚铁血红素蛋白形成相对稳定的加合物，在 NOS 的情况下，它也是关键的催化中间体。尽管对其他血红素蛋白的亚铁亚硝酰复合物进行了广泛的研究（特别是肌红蛋白），但在 NOS 的情况下，其特征描述很少。我们在这里报告了对诱导型哺乳动物 NOS 和枯草芽孢杆菌的细菌 NOS 样蛋白的亚铁亚硝酰复合物的温度依赖性 EPR 研究。结果表明，整体行为与其他血红素蛋白观察到的相似，但在两种 NOS 蛋白的情况下，轴向和菱形形式之间的比例不同。远端环境似乎控制着轴向形式的存在和菱形形式的演变。
