Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India.
J Biomol NMR. 2013 Jun;56(2):77-84. doi: 10.1007/s10858-013-9735-9. Epub 2013 May 5.
We present here an NMR pulse sequence with 5 independent incrementable time delays within the frame of a 3-dimensional experiment, by incorporating polarization sharing and dual receiver concepts. This has been applied to directly record 3D-HA(CA)NH and 3D-HACACO spectra of proteins simultaneously using parallel detection of (1)H and (13)C nuclei. While both the experiments display intra-residue backbone correlations, the 3D-HA(CA)NH provides also sequential 'i - 1 → i' correlation along the (1)Hα dimension. Both the spectra contain special peak patterns at glycine locations which serve as check points during the sequential assignment process. The 3D-HACACO spectrum contains, in addition, information on prolines and side chains of residues having H-C-CO network (i.e., (1)Hβ, (13)Cβ and (13)COγ of Asp and Asn, and (1)Hγ, (13)Cγ and (13)COδ of Glu and Gln), which are generally absent in most conventional proton detected experiments.
我们在这里提出了一种 NMR 脉冲序列，该序列在三维实验的框架内具有 5 个独立的可增量时间延迟，通过结合极化共享和双接收体概念实现。该方法已应用于同时直接记录蛋白质的 3D-HA(CA)NH 和 3D-HACACO 谱，同时平行检测 (1)H 和 (13)C 核。虽然这两个实验都显示了残基内的骨架相关性，但 3D-HA(CA)NH 还提供了沿着 (1)Hα 维度的顺序“i - 1 → i”相关性。两个谱都在甘氨酸位置显示出特殊的峰型模式，这些模式在序列分配过程中作为检查点。3D-HACACO 谱除了包含脯氨酸和具有 H-C-CO 网络的残基侧链信息（即 Asp 和 Asn 的 (1)Hβ、(13)Cβ 和 (13)COγ，以及 Glu 和 Gln 的 (1)Hγ、(13)Cγ 和 (13)COδ）之外，这些信息通常在大多数常规质子检测实验中都不存在。
