Department of Physics Indian Institute of Technology-Madras, Chennai 600036 India.
J Biomol Struct Dyn. 2010 Feb;27(4):561-72. doi: 10.1080/07391102.2010.10507339.
There has been much recent progress in using NMR chemical shift anisotropy (CSA) parameters to gain information about secondary structure content in proteins. This paper focuses on the comparison of CSA tensors of different backbone nuclei (namely 13C(a), 13C', 15N, 1H(a), 1H(N)) of all twenty amino acids appearing in well- defined secondary structures such as helices and sheets. Dihedral angle information of these backbone nuclei in different secondary structure elements has been extracted from experimentally determined structures of proteins deposited in the protein databank. The CSA tensors of these backbone nuclei have been computed for the corresponding dihedral angles using ab initio quantum chemical methods. It is shown that 2D correlated plots of a novel set of CSA parameters (r,t), that define the magnitude and shape of the anisotropy, are extremely useful in identifying secondary structure content. Further, multinuclear correlations between these CSA parameters can clearly distinguish between various secondary structure elements such as helices and sheets.
近年来，利用核磁共振化学位移各向异性（CSA）参数获取蛋白质二级结构含量信息方面取得了很大进展。本文主要比较了在明确的二级结构（如螺旋和片层）中出现的所有二十种氨基酸的不同骨架核（即 13C(a)、13C'、15N、1H(a)、1H(N)）的 CSA 张量。从蛋白质数据库中储存的蛋白质实验确定结构中提取了这些骨架核在不同二级结构元素中的二面角信息。使用从头算量子化学方法，针对相应的二面角计算了这些骨架核的 CSA 张量。结果表明，一套新的 CSA 参数（r，t）的二维相关图（定义各向异性的大小和形状）在识别二级结构含量方面非常有用。此外，这些 CSA 参数之间的多核相关性可以清楚地区分各种二级结构元件，如螺旋和片层。
