对19F的静电贡献 在蛋白质中的酸酸中发生的化学转变
Michael Maxwell1, Yi Jiun Tan1, Richmond Lee2
1Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra 2601, Australian Capital Territory, Australia.
Biochemistry
|November 7, 2023
概括
这项研究调查了-19 (19F) 化学转移在突变后蛋白质的变化. 结果显示,19F变化对电荷变化敏感,但与理论预测不同,受蛋白质环境的抑制.
科学领域:
- 生物物理化学 生物物理化学
- 蛋白质NMR光谱法 蛋白质NMR光谱法
- 计算化学计算化学
背景情况:
- 核磁共振 (NMR) 光谱是研究蛋白质结构和动态的强大工具.
- -19 (19F) 核磁共振具有独特的优势,因为的自然丰度很低,敏感度很高.
- 电场显著影响19F的化学转移,这表明长距离结构信息的潜力.
研究的目的:
- 为了评估19F化学转移在托坦残留中的实用性,作为蛋白质中的远程结构探针.
- 研究电荷突变对不同蛋白质环境中的19F化学转移的影响.
- 为了比较19F化学转移与1H化学转移对电荷扰动的灵敏度.
主要方法:
- 通过无细胞蛋白质合成,将四种二二异构体 (4-, 5-, 6-, 7-FT) 具体地纳入两个蛋白质 (GB1和NT*域) 中.
- 引入充电突变,通过将阿斯巴拉金转化为酸残留物.
- 在突变蛋白质中测量氧酸残留的19F化学转移和非化对照的1H化学转移.
- 实验19F化学转移变化与密度函数理论 (DFT) 计算预测的比较.
主要成果:
- 19F在托坦残留物中的化学变化对引入的电荷突变显示出敏感性.
- 19F化学转移变化的大小明显小于真空中DFT计算预测的.
- 观察到的19F化学转移变化在非化对照中比1H化学转移变化更为明显.
- 没有发现转移的大小和电荷突变距离之间的简单相关性.
结论:
- 虽然19F化学转移对电荷扰动敏感,但它们对于远程结构约束的实用性受到蛋白质和溶剂的显著介电屏蔽限制.
- 实验结果强调了在解释19F NMR数据时考虑蛋白质的介电环境的重要性.
- 需要进一步的研究来完善对结构生物学应用中的19F化学转移的解释.
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