对13MDa病毒囊的成熟中间体的溶液NMR研究
Blair R Szymczyna1, Lu Gan, John E Johnson
1Department of Molecular Biology, The Skaggs Institute for Chemical Biology and The Center for Integrative Molecular Biosciences, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Journal of the American Chemical Society
|June 1, 2007
概括
动态蛋白质区域对于功能至关重要. 核磁共振 (NMR) 谱学揭示了细菌HK97 procapsids在成熟过程中的动态N-终端,补充了结构研究.
科学领域:
- 结构生物学是结构生物学.
- 生物物理学的生物物理.
- 分子生物学分子生物学
背景情况:
- 动态蛋白质区域对于宏分子复合体的组装和功能至关重要.
- 射线晶体学和冷电子显微镜通常会丢失灵活蛋白质区域的信息.
- 羔羊状细菌 HK97 作为研究宏分子成熟的模型系统.
研究的目的:
- 研究细菌 HK97囊成熟过程中必需蛋白质区域的动态行为.
- 通过使用溶液核磁共振 (NMR) 光谱学来描述无序区域来补充现有的结构数据.
- 了解N终端动态在HK97.97成熟过程中的作用.
主要方法:
- 使用溶液核磁共振 (NMR) 光谱学研究了HK97体的动态N-终端.
- 使用NMR进行了残留特定的分配和行为评估.
- 随着时间的推移,对成熟过程中的N端残留物变化进行了监测.
主要成果:
- 在HK97 procapsids的N-终端残留物和E-循环在早期成熟阶段表现出显著的混乱.
- 核磁共振在前体和未成熟状态下确定了N-终端与内部体表面的短暂相互作用.
- 在EI-III状态下的N-终端随着时间的推移显示出更大的灵活性,在完全成熟的Head II囊中没有观察到共振.
结论:
- 核磁共振光谱学提供了对基本蛋白质区域的动态的关键见解,这些区域无法通过结晶学或冷EM解决.
- 动态的N端在HK97的成熟过程中发挥作用,经历了形状变化.
- 该研究强调了NMR和其他结构技术的互补性质,以全面了解宏分子动力学.
相关概念视频
Carbon-13 (¹³C) NMR: Overview
Carbon-13 is a naturally occurring NMR-active isotope of carbon with a low natural abundance of 1.1%. In contrast, carbon-12 is the most abundant isotope of carbon with zero nuclear spin. Therefore, it is NMR inactive. The gyromagnetic ratio of carbon-13 is smaller than that of protons. As a result, carbon-13 resonance is about 6000 times weaker than proton resonance. For a given magnetic field strength, the resonance frequency of carbon-13 is about one-fourth of the resonance frequency for...
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
¹³C NMR: ¹H–¹³C Decoupling
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...


