Clubb R T, Thanabal V, Wagner G
Department of Biological Chemistry, Harvard Medical School, Boston, MA 02115.
J Biomol NMR. 1992 Mar;2(2):203-10. doi: 10.1007/BF01875531.
A new 3D 1H-15N-13C triple resonance experiment is presented that provides in-phase absorptive cross peaks between amide protons and alpha-protons of the same and the sequentially preceding residue. The experiment yields similar connectivities as those described previously by Montelione and Wagner (1990a) (J. Magn. Reson., 87, 183-188) and Kay et al. (1991) (J. Magn. Reson., 91, 84-92). However, the pulse sequence was designed to minimize the time that transverse coherence of the 13Calpha nucleus is present, since this nucleus has the shortest transverse relaxation time of all the nuclei involved in these experiments. This is achieved by using a coherence transfer pathway from 1HN to 15N, 13Calpha, 1Halpha and back to the 1HN. In the sequence described, transverse 13Calpha coherence is present only for a length of ca. 1/1J(Calpha-Halpha). This reduces loss of signal due to transverse relaxation. We tested the technique on uniformly 15N- and 13C-enriched T4 lysozyme.
本文提出了一种新的3D 1H-15N-13C三共振实验，该实验可在同一残基及其前一个残基的酰胺质子和α-质子之间提供同相吸收交叉峰。该实验产生的连接性与Montelione和Wagner（1990a）（《磁共振杂志》，87，183-188）以及Kay等人（1991）（《磁共振杂志》，91，84-92）先前描述的类似。然而，该脉冲序列的设计目的是尽量减少13Cα核横向相干存在的时间，因为在这些实验涉及的所有核中，该核的横向弛豫时间最短。这是通过使用从1HN到15N、13Cα、1Hα再回到1HN的相干转移路径来实现的。在所描述的序列中，横向13Cα相干仅存在约1/1J（Cα-Hα）的时长。这减少了由于横向弛豫导致的信号损失。我们在均匀15N和13C富集的T4溶菌酶上测试了该技术。
