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在血红素添加物中通过NO和CO振动对蛋白质影响的差异感知
Mohammed Ibrahim1, Changliang Xu, Thomas G Spiro
1Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
Journal of the American Chemical Society
|December 21, 2006
概括
血红蛋白与氧化 (NO) 和一氧化碳 (CO) 的结合方式不同. 新的研究揭示了不同于CO的NO adducts中的振动模式,为血红素传感蛋白功能提供了洞察力.
科学领域:
- 生物化学 生物化学
- 频谱学是一种光谱学.
- 计算化学的计算化学
背景情况:
- 血红蛋白利用Fe d(pi) 背链结合,结合一氧化碳 (CO) 和一氧化 (NO) 等气体连接物.
- 蛋白质相互作用和转链体强度调节这种背链,影响Fe-X和X-O键的振动模式.
- 基于nuFeC/nuCO反相对关系的CO引证的现有解释框架并没有很容易适用于NO引证.
研究的目的:
- 为了研究和建立在血红蛋白中铁-氧化物 (FeNO) 键的振动模式反相关性.
- 为了比较蛋白质中氧化 (NO) 和一氧化碳 (CO) 添加物的结合和振动特性.
- 阐明远端蛋白相互作用在调节血红蛋白传感器蛋白中的连接体结合和信号机制中的作用.
主要方法:
- 共振拉曼光谱法用于分析 (N-methylimidazole) Fe ((II) TPP-Y ((NO) 和相关的CO添加物的冷溶液中的NO和CO添加物的振动模式.
- 合成了多种替代剂 (Y) 的四甲 (TPP) 衍生物,以调节电子性质和背接.
- 进行了密度函数理论 (DFT) 计算,以支持振动模式的结构和光谱分析.
主要成果:
- 对于NO adducts,观察到nuFeN和nuNO振动模式之间的优良反相对应,类似于CO adducts.
- DFT计算支持了实验结果,证实了观察到的反相关性,并提供了结构性见解.
- 在有远距离键或正电荷的情况下,观察到与NO adducts的模拟反相对应的偏差,这些偏差归因于FeNO角度变化.
结论:
- 已建立的nuFeN/nuNO抗相关性为理解NO与血红蛋白的结合提供了一个框架,类似于CO附加物.
- 远端蛋白相互作用显著影响NO结合几何和电子结构,导致从基线反相关性偏差.
- 不同的NO和CO adducts的振动模式提供了补充信息,用于解读血红素传感器蛋白中的联体区分和信号通路.
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