Ying Jinfa, Roche Julien, Bax Ad
Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
J Magn Reson. 2014 Apr;241:97-102. doi: 10.1016/j.jmr.2013.11.006. Epub 2013 Nov 22.
Application of band-selective homonuclear (BASH) (1)H decoupling pulses during acquisition of the (1)H free induction decay is shown to be an efficient procedure for removal of scalar and residual dipolar couplings between amide and aliphatic protons. BASH decoupling can be applied in both dimensions of a homonuclear 2D NMR experiment and is particularly useful for enhancing spectral resolution in the H(N)-H(α) region of NOESY spectra of peptides and proteins, which contain important information on the backbone torsion angles. The method then also prevents generation of zero quantum and Hz(N)-Hz(α) terms, thereby facilitating analysis of intraresidue interactions. Application to the NOESY spectrum of a hexapeptide fragment of the intrinsically disordered protein α-synuclein highlights the considerable diffusion anisotropy present in linear peptides. Removal of residual dipolar couplings between H(N) and aliphatic protons in weakly aligned proteins increases resolution in the (1)H-(15)N HSQC region of the spectrum and allows measurement of RDCs in samples that are relatively strongly aligned. The approach is demonstrated for measurement of RDCs in protonated (15)N/(13)C-enriched ubiquitin, aligned in Pf1, yielding improved fitting to the ubiquitin structure.
在采集¹H自由感应衰减信号期间应用带选择性同核（BASH）¹H去耦脉冲，被证明是去除酰胺质子与脂肪族质子之间标量耦合和残余偶极耦合的有效方法。BASH去耦可应用于同核二维核磁共振实验的两个维度，对于提高肽和蛋白质的NOESY谱中H(N)-H(α)区域的光谱分辨率特别有用，该区域包含有关主链扭转角的重要信息。该方法还可防止零量子项和Hz(N)-Hz(α)项的产生，从而便于分析残基内相互作用。将其应用于内在无序蛋白α-突触核蛋白的六肽片段的NOESY谱，突出了线性肽中存在的显著扩散各向异性。去除弱对齐蛋白质中H(N)和脂肪族质子之间的残余偶极耦合，可提高谱图¹H-(¹⁵)N HSQC区域的分辨率，并允许在相对强对齐的样品中测量残余偶极耦合（RDC）。该方法已在质子化的¹⁵N/¹³C富集泛素中测量RDC得到证明，泛素在Pf1中对齐，对泛素结构的拟合得到改善。
