作为多维数据收集的总体策略,NMR的高分辨率代频率识别是多维数据收集的一般策略
Hamid R Eghbalnia1, Arash Bahrami, Marco Tonelli
1National Magnetic Resonance Facility at Madison, Center for Eukaryotic Structural Genomics, Graduate Program in Biophysics, Biochemistry Department, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA. eghbalni@nmrfam.wisc.edu
Journal of the American Chemical Society
|September 8, 2005
概括
高分辨率代频率识别NMR (HIFI-NMR) 快速收集和处理多维NMR数据. 这种新的方法显著减少了数据收集和处理的时间,实现了蛋白质共振分配的高精度.
科学领域:
- 核磁共振 (NMR) 光谱学 核磁共振 (NMR) 光谱学
- 结构生物学 结构生物学
- 计算化学计算化学
背景情况:
- 多维NMR对于确定蛋白质结构和动态至关重要.
- 目前收集和处理数据的方法可能是耗时和计算密集的.
- 减少维度的方法提供更快的数据采集,但需要高效的处理算法.
研究的目的:
- 引入一种新的,用于多维NMR数据收集和处理的快速方法,称为HIFI-NMR.
- 开发一种算法,以适应方式选择数据收集平面,并统计模型光谱空间.
- 为了实现直接生成概率性峰值列表,以实现高效的蛋白质共振分配.
主要方法:
- 根据统计分析,HIFI-NMR采集n维数据作为一系列的2D平面,根据统计分析适应性选择倾斜的平面.
- 一个在线算法模型3D峰值位置概率,优化下一个平面的选择和确定数据收集终止.
- 强大的统计算法处理平面投影来驱动数据收集,并直接生成峰值列表与相关的概率.
主要成果:
- 在3D三重共振实验中,HIFI-NMR成功地确定了大约98%的真实峰值,用于小型和大型蛋白质.
- 与传统的3DNMR方法相比,数据收集时间缩短了大约十倍.
- 该方法直接生成了带有概率的峰值列表,绕过了广泛的采购后处理和峰值选择.
结论:
- 在多维NMR数据采集和处理的速度和效率方面,HIFI-NMR提供了显著的进步.
- 这种方法的准确性很高,与传统方法相美,同时大大缩短了实验时间.
- HIFI-NMR可以在商业光谱仪上实现,并可扩展到更高维度的NMR研究,从而促进更快的蛋白质结构确定.
相关概念视频
01:20NMR Spectrometers: Overview
NMR spectrometers consist of a strong magnet, a radiofrequency transmitter, and a detector attached to a computer console for recording spectra of samples containing NMR-active nuclei. In first-generation NMR instruments called continuous-wave spectrometers, the resonance frequencies of the nuclei are determined by frequency-sweep or field-sweep methods. The magnetic field strength is fixed and the rf signal is swept in the former, while the radiofrequency signal is fixed and the magnetic field...
01:12Two-Dimensional (2D) NMR: Overview
The 1D NMR spectrum of large and complex molecules like natural products has complicated splitting patterns and overlapping signals, which can be easily interpreted using 2-dimensional (2D) NMR. Unlike 1D NMR, 2D NMR has two frequency axes that provide the coupling information between the nucleus A and nucleus B in a molecule. The process from which 2D spectra are obtained has four steps.
The first step is the preparation period, during which nucleus A is excited with a radiofrequency pulse.
The first step is the preparation period, during which nucleus A is excited with a radiofrequency pulse.
01:13¹H NMR Signal Multiplicity: Splitting Patterns
When protons A and X are coupled, their nuclear spin energy levels are slightly modified. This is because the energy required to excite proton A to a spin state parallel to proton X is slightly different from the energy required for it to become anti-parallel to spin X. Consequently, there are two possible excitation frequencies for A (A1 and A2), depending on the spin state of X, and vice versa. The mutual nature of coupling implies that the difference between frequencies A1 and A2, indicated...
01:17NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.
01:25Applications Of NMR In Biology
Nuclear magnetic resonance (NMR) spectroscopy is a very valuable analytical technique for researchers. It has been used for more than 50 years as an analytical tool. F. Bloch and E. Purcell formulated NMR in 1946 and won the 1952 Nobel Prize in Physics for their work. Biological macromolecules such as proteins, nucleic acids, lipids, and organic molecules including pharmaceutical compounds, can be studied using this versatile tool that exploits the magnetic properties of certain nuclei.
The...
The...
01:182D NMR: Overview of Heteronuclear Correlation Techniques
Heteronuclear correlation spectroscopy is an analytical technique that investigates the coupling between different types of nuclei, often a proton and an X-nucleus, such as carbon-13 or nitrogen-15. This method is commonly used in nuclear magnetic resonance (NMR) spectroscopy to gain insights into complex chemical compounds' structural and compositional aspects. A typical heteronuclear correlation spectrum displays X-nucleus chemical shifts on one axis and a proton spectrum on the other axis.