4,4-Difluoroproline作为一个独特的F NMR探测器的proline构造
Himal K Ganguly1, Brice A Ludwig1, Caitlin M Tressler1
1Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States.
Biochemistry
|April 10, 2024
概括
4,4-Difluoroproline (Dfp) 是一种新型的探针,用于研究使用19F NMR. 它揭示了proline环的偏好和cis-trans异构体,有助于蛋白质折叠和疾病研究.
科学领域:
- 生物化学 生物化学
- 化学生物学 化学生物学
- 结构生物学 结构生物学
背景情况:
- 氨酸构成对蛋白质结构和功能至关重要,但检测它的方法有限.
- 了解氨酸的 cis-trans 同位体和环 (exo/endo) 是蛋白质折叠和动态的关键.
- 现有的技术对于研究proline形状偏好缺乏方便性.
研究的目的:
- 为了引入4,4-Difluoroproline (Dfp) 作为一种敏感的19F NMR探针,用于素构成.
- 为了确定Dfp的19F NMR化学转移与普罗林的构造状态之间的关系.
- 应用Dfp用于研究和蛋白质中的proline异构体.
主要方法:
- 4,4-Difluoroproline (Dfp) 的合成和表征.
- 在模型化合物和中Dfp的19FNMR光谱.
- 密度函数理论 (DFT) 的计算.
- X射线晶体学和固态NMR光谱学.
- 适用于内在无序的蛋白质和变质的状态.
主要成果:
- Dfp的二氧化含量表现出明显的化学转移差异 (ΔδFF),与cis-trans胺基键和环相相关.
- 一个小的 ΔδFF (0-3 ppm) 表示无序的普罗林 (转胺,外/内的混合物).
- 一个大的 ΔδFF (5-12 ppm) 表示有序的普罗林 (cis amide,受欢迎的endo pucker).
- Dfp在8M尿素中的聚烯II螺旋 (PPII) 中发现了相同的外/内.
- Dfp量化了由于酸化和tau蛋白的突变而导致的proline cis-trans异构体变化.
结论:
- Dfp是一种多功能的19F核磁共振探针,用于检测proline构成平衡和cis-trans异构.
- 该探测器提供了对内在无序蛋白质和蛋白质折叠的局部秩序的洞察.
- 由于DFP的最小固体影响,可以将其纳入表达蛋白质中,用于广泛的应用.
- 这些发现支持碳基溶解和n → π*相互作用在PPII稳定中的作用.
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