Svistunenko Dimitri A, Davies Nathan, Brealey David, Singer Mervyn, Cooper Chris E
Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK.
Biochim Biophys Acta. 2006 Apr;1757(4):262-72. doi: 10.1016/j.bbabio.2006.03.007. Epub 2006 Mar 30.
Electron paramagnetic resonance (EPR) spectra of complex biological systems contain information about the paramagnetic centres present. Retrieving such information is important since paramagnetic species are common intermediates of all redox reactions in both normal and abnormal metabolism. However, it is often difficult to determine the nature and content of all paramagnetic species present because the EPR signals from individual centres overlap. Here, we apply our deconvolution method based on spectra subtraction with variable coefficient to quantify individual paramagnetic components of human muscle biopsies taken from critically ill patients with severe sepsis. We use low temperature EPR spectroscopy to identify and quantify nine different paramagnetic species in the tissue. These include the majority of the mitochondrial iron-sulfur centres and the first in vivo report of a mitochondrial radical assigned to a spin-coupled pair of semiquinones (SQ*-SQ*). We have previously demonstrated in these same muscle biopsies that biochemical assays of mitochondrial dysfunction correlate with clinical outcomes (D. Brealey, M. Brand, I. Hargreaves, S. Heales, J. Land, R. Smolenski, N.A. Davies, C.E. Cooper, M. Singer, Association between mitochondrial dysfunction and severity and outcome of septic shock. Lancet 360 (2002) 219-223.). Analysis of the paramagnetic centres in the muscle confirms and extends these findings: the (SQ*-SQ*) radical species negatively correlates with the illness severity of the patient (APACHE II score) and a decreased concentration of mitochondrial Complex I iron-sulfur redox centres is linked to mortality.
复杂生物系统的电子顺磁共振（EPR）光谱包含有关存在的顺磁中心的信息。获取此类信息很重要，因为顺磁物质是正常和异常代谢中所有氧化还原反应的常见中间体。然而，由于来自各个中心的EPR信号相互重叠，通常很难确定所有存在的顺磁物质的性质和含量。在此，我们应用基于可变系数光谱减法的去卷积方法，对从患有严重脓毒症的重症患者身上采集的人体肌肉活检样本中的各个顺磁成分进行定量分析。我们使用低温EPR光谱法来识别和定量组织中的九种不同顺磁物质。其中包括大多数线粒体铁硫中心，以及首次在体内报道的一种线粒体自由基，该自由基被确定为一对自旋耦合的半醌（SQ*-SQ*）。我们之前在这些相同的肌肉活检样本中证明，线粒体功能障碍的生化检测结果与临床结果相关（D. 布雷利、M. 布兰德、I. 哈格里夫斯、S. 希尔斯、J. 兰德、R. 斯莫伦斯基、N.A. 戴维斯、C.E. 库珀、M. 辛格，线粒体功能障碍与脓毒性休克的严重程度和结果之间的关联。《柳叶刀》360（2002年）219 - 223页）。对肌肉中顺磁中心的分析证实并扩展了这些发现：（SQ*-SQ*）自由基种类与患者的疾病严重程度（急性生理与慢性健康状况评分系统II评分）呈负相关，线粒体复合物I铁硫氧化还原中心浓度降低与死亡率相关。
