蛋白质中的电子介导Cu (A) 中心:一个比较高场的 (1) H ENDOR研究
Boris Epel1, Claire S Slutter, Frank Neese
1Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel.
高场电子核双共振 (ENDOR) 揭示了各种蛋白质的铜A中心的自旋密度分布. 这项研究将结构特征与电子转移功能相关联,为蛋白质机制提供了洞察力.
科学领域:
- 生物物理学的生物物理.
- 生物化学 生物化学
- 频谱学是一种光谱学.
背景情况:
- 双核铜A (Cu(A)) 中心对于像氧化减少酶和细胞染色体c氧化酶这样的蛋白质中电子转移至关重要.
- 了解Cu (A) 中心的电子结构和旋转密度分布是阐明其功能的关键.
- 高场脉冲电子核双共振 (ENDOR) 是一种强大的技术,用于探测金属蛋白中的金属-连接体相互作用.
研究的目的:
- 为了研究各种蛋白质在Cu(A) 中心内的自旋密度分布,使用高场 (W波段) 脉冲ENDOR.
- 通过分析氨酸和氨酸质子的超细相互作用,通过分析氨酸和氨酸质子的超细相互作用,将结构特征与电子转移特性相关联.
- 为了比较不同蛋白质环境中的Cu (A) 中心的电子和结构特征.
主要方法:
- 高场 (95 GHz) 脉冲电子核双共振 (ENDOR) 测量了氧化减少酶 (N(2) OR),Thermus thermophilus 细胞染色体c氧化酶 (COX) ba(3) (M160T9),其M160QT0突变体,以及工程紫色氨酸 (purpAz).
- 对电子磁共振 (EPR) 和ENDOR光谱的分析,以识别和描述不同的质子信号 (氨酸β-质子,氨酸H (氨酸) 质子,胺质子).
- 定向选择性ENDOR光谱学和光谱模拟以确定同位素和异位素超细相互作用并估计硫旋密度.
主要成果:
- ENDOR光谱揭示了强度合的氨酸β-质子和弱合的质子,主要是氨酸H ((epsilon) ((1) 和胺质子的独特信号.
- 在β-质子的同位素高精度合和铜高精度相互作用之间观察到线性相关性.
- 在研究的蛋白质中,硫旋密度和过联结贡献各不相同,M160T9显示最大,purpAz显示最低.
- 与Cu(2) S(2) 核心相对的伊米达环位置的差异是从弱合质子的分裂模式推断出来的.
结论:
- 高场脉冲ENDOR成功地解决和表征了各种蛋白质的Cu (A) 中心内的超细相互作用.
- 该研究提供了自旋密度分布的定量估计,并突出了蛋白质结构对Cu (A) 电子性质的影响.
- 研究结果表明,旋转密度分布,结构细微差别和Cu (A) 中心的电子转移功能之间存在潜在的相关性.
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