Pannetier Nicolas, Houben Klaartje, Blanchard Laurence, Marion Dominique
Institut de Biologie Structurale Jean-Pierre Ebel CEA - CNRS - UJF, 41, Rue Jules Horowitz, 38027 Grenoble Cedex, France.
J Magn Reson. 2007 May;186(1):142-9. doi: 10.1016/j.jmr.2007.01.013. Epub 2007 Jan 23.
Resonance assignment of NMR spectra of unstructured proteins is made difficult by severe overlap due to the lack of secondary structure. Fortunately, this drawback is partially counterbalanced by the narrow line-widths due to the internal flexibility. Alternate sampling schemes can be used to achieve better resolution in less experimental time. Deterministic schemes (such as radial sampling) suffer however from the presence of systematic artifacts. Random acquisition patterns can alleviate this problem by randomizing the artifacts. We show in this communication that quantitative well-resolved spectra can be obtained, provided that the data points are properly weighted before FT. These weights can be evaluated using the concept of Voronoi cells associated with the data points. The introduced artifacts do not affect the direct surrounding of the peaks and thus do not alter the amplitude and frequency of the signals. This procedure is illustrated on 60-residue viral protein, which lacks any persistent secondary structure and thus exhibits major signal overlap.
由于缺乏二级结构，无结构蛋白的核磁共振谱共振归属因严重重叠而变得困难。幸运的是，由于内部灵活性导致的窄线宽在一定程度上抵消了这一缺点。可以使用交替采样方案在更短的实验时间内获得更好的分辨率。然而，确定性方案（如径向采样）存在系统伪影。随机采集模式可以通过使伪影随机化来缓解这一问题。我们在本通讯中表明，只要在傅里叶变换之前对数据点进行适当加权，就可以获得定量的高分辨率谱。这些权重可以使用与数据点相关的沃罗诺伊单元的概念来评估。引入的伪影不会影响峰的直接周围环境，因此不会改变信号的幅度和频率。该过程在一个由60个残基组成的病毒蛋白上得到了说明，该蛋白缺乏任何持久的二级结构，因此表现出严重的信号重叠。
