Comparison of maximum quantum filtered NMR spectroscopy (MAXY NMR) and other two-dimensional NMR approaches for resonance assignment of peptides
Comparison of maximum quantum filtered NMR spectroscopy (MAXY NMR) and other two-dimensional NMR approaches for resonance assignment of peptides
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DOI：
10.1002/(sici)1097-458x(199611)34:11
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发表时间：
1996-11-01
影响因子：
2
通讯作者：
Tranter, GE
中科院分区：
文献类型：
--
作者：
Liu, M;Nicholson, JK;Tranter, GE
利用二维H-1检测的最大量子滤波核磁共振谱对神经降压素十三肽在三氟乙醇溶液中的H-1和C-13核磁共振谱进行了归属特别地，选择性检测来自亮氨酸和异亮氨酸残基的CH质子，其通常被CH 2共振掩盖，的MAXY-TOCSY实验的使用，促进了个别亚甲基质子的氨基酸与重叠的亚甲基共振的识别，该方法相比，使用传统的TOCSY光谱。一个新的脉冲序列，Gem-TOCSY，被证明和它的相对有用性也被讨论在肽共振分配的上下文中。核磁共振结果表明构象互换，这是缓慢的核磁共振时间尺度上，顺式和反式构象之间的脯氨酸-10。构象依赖的数据，包括耦合常数，酰胺质子化学位移温度系数，从ROESY实验和圆二色光谱获得的NOE表明，神经降压素在三氟乙醇溶液中是柔性的，没有单一的固定构象占主导地位，然而，这项工作清楚地表明了MAXY NMR方法在H-NMR中高度重叠共振归属的普遍应用的潜力。肽和蛋白质的1 NMR谱。
The H-1 and C-13 NMR spectra of the tridecapeptide neurotensin were assigned in trifluoroethanol solution with the help of two-dimensional H-1-detected maximum quantum filtered NMR spectroscopy (MAXY NMR), which allows the separate detection of CH, CH2 and CH3 H-1 NMR resonances, In particular, the selective detection of CH protons from leucine and isoleucine residues, normally obscured by CH2 resonances, was facilitated by the use of the MAXY-TOCSY experiment, as was the identification of individual methylene protons in amino acids with overlapping methylene resonances, The approach is compared with the use of conventional TOCSY spectroscopy. A new pulse sequence, gem-TOCSY, is demonstrated and its relative usefulness is also discussed in the context of peptide resonance assignment. The NMR results demonstrated conformational interchange, which was slow on the NMR time-scale, between cis and trans conformers of proline-10. Conformation-dependent data, including coupling constants, amide proton chemical shift temperature coefficients, NOEs obtained from a ROESY experiment and circular dichroism spectra indicated that neurotensin in trifluoroethanol solution is flexible with no single fixed conformation predominating, Nevertheless, this work demonstrates clearly the potential for the general application of the MAXY NMR approach to the assignment of highly overlapped resonances in H-1 NMR spectra of peptides and proteins.