细胞色素c甲硫氨酸氧化机制的NMR研究  

NMR Study on the Mechanism of Cytochrome c Methionine Oxidation

作　　者：赵蓓蓓 占建华 胡琴 朱勤俊 刘买利 张许 ZHAO Beibei;ZHAN Jianhua;HU Qin;ZHU Qinjun;LIU Maili;ZHANG Xu(State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,National Center for Magnetic Resonance in Wuhan(Innovation Academy for Precision Measurement Science and Technology,Chinese Academy of Sciences),Wuhan 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Wuhan National Research Center for Optoelectronics,Huazhong University of Science and Technology,Wuhan 430074,China;Optics Valley Laboratory,Wuhan 430074,China)

机构地区：[1]波谱与原子分子物理国家重点实验室,武汉磁共振中心(中国科学院精密测量科学与技术创新研究院),湖北武汉430071 [2]中国科学院大学,北京100049 [3]华中科技大学武汉光电国家研究中心,湖北武汉430074 [4]湖北光谷实验室,湖北武汉430074

出　　处：《波谱学杂志》2023年第3期246-257,共12页Chinese Journal of Magnetic Resonance

基　　金：国家重点基础研究发展计划(“973”计划)资助项目(2017YFA0505400,2018YFE0202300,2018YFA0704002)。

摘　　要：细胞在呼吸作用中产生活性氧,活性氧含量处于低水平时有利于信号传导,累积过量时会引发蛋白质氧化修饰.细胞色素c是位于线粒体内的多功能金属蛋白,其发生氧化修饰特别是甲硫氨酸Met80的亚砜化修饰可能影响蛋白构象变化,但其机制仍不清楚.本研究通过13C选择性标记细胞色素c上甲硫氨酸的末端甲基,利用液体核磁共振技术,追踪了细胞色素c在氧化环境中的氧化修饰变化.发现在氧化环境中,该蛋白质先由还原态转化为氧化态,当活性氧达到一定量时,再发生甲硫氨酸Met80的亚砜化修饰,但在活性氧作用初期未导致明显的蛋白结构变化.这表明细胞色素c具有一定抵御活性氧的作用.Mitochondria generate reactive oxygen species(ROS)during respiration.Low levels of ROS are conducive to signal transduction,whereas excessive accumulation of ROS can lead to protein oxidative modification.Cytochrome c(cyt c)is a multifunctional metalloprotein located in mitochondria.The oxidative modification of cyt c,especially the Met80 has been found to result in conformational change,but the mechanism is still unclear.In this study,the terminal methyl group of methionine on cytochrome c was selectively labeled with 13C,and the modification of the methionine in cytochrome c under oxidative environments was tracked by NMR.It was observed that under oxidative environments,the protein was first converted from reduced state to oxidized state,then oxidatively modified.The oxidative modification of Met80 occurred under relatively high content of ROS,but did not result in distinctive conformation transition.The result suggests that the protein has high activity to resist ROS damage,therefore,plays a regulatory role in inhibiting apoptosis.

关 键 词：氧化修饰 细胞色素C 液体核磁共振 选择性标记 

分 类 号：O482.53[理学—固体物理]