Neighboring Residue Effects in Terminally Blocked Dipeptides: Implications for Residual Secondary Structures in Intrinsically Unfolded/Disordered Proteins
Neighboring Residue Effects in Terminally Blocked Dipeptides: Implications for Residual Secondary Structures in Intrinsically Unfolded/Disordered Proteins
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DOI：
10.1002/chir.22285
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发表时间：
2014-09-01
期刊：
影响因子：
2
通讯作者：
Cho, Minhaeng
中科院分区：
文献类型：
--
作者：
Jung, Young-Sang;Oh, Kwang-Im;Cho, Minhaeng
对于基于核磁共振（NMR）的蛋白质结构测定，无规卷曲化学位移是非常重要的，因为通过检查测量的化学位移与这些参考化学位移值的偏差，可以预测蛋白质的二级和三级结构。此外，相邻残基的化学位移和J-耦合常数的影响是至关重要的，在理解未折叠或内在无序的蛋白质所表现出的构象倾向的性质。我们最近报道了一整套末端封闭的二肽的1D NMR结果（Oh KI，Jung YS，Hwang GS，Cho M. J Biomol NMR 2012; 53：25-41），但NMR共振归属是不可能的，因此仅考虑平均化学位移和J-偶合常数。在本工作中，为了彻底研究相邻残基效应和无规卷曲化学位移，我们扩展了以前的研究与二维NMR，并测量了所有的（3）J（HNH α）值和H-α和HN化学位移的相同的一组末端封闭的二肽，是免费的结构效应，如二级结构，氢键，长程骨干，和侧链相互作用。特别是，前面和后面的残基对氨基酸骨架构象倾向的影响被揭示出来，并直接与以前的工作相比，无论是短肽或经验化学位移数据库。(C)2014 Wiley Periodicals，Inc.
For nuclear magnetic resonance (NMR)-based protein structure determinations, the random coil chemical shifts are very important because the secondary and tertiary protein structure predictions become possible by examining deviations of measured chemical shifts from those reference chemical shift values. In addition, neighboring residue effects on chemical shifts and J-coupling constants are crucial in understanding the nature of conformational propensities exhibited by unfolded or intrinsically disordered proteins. We recently reported the 1D NMR results for a complete set of terminally blocked dipeptides (Oh KI, Jung YS, Hwang GS, Cho M. J Biomol NMR 2012; 53: 25-41), but the NMR resonance assignments were not possible so that the average chemical shifts and J-coupling constants were only considered. In the present work, to thoroughly investigate the neighboring residue effects and random coil chemical shifts we extend the previous studies with 2D NMR, and measured all the (3)J(HNH alpha) values and H-alpha and HN chemical shifts of the same set of terminally blocked dipeptides that are free from structural effects like secondary structure, hydrogen-bond, long-range backbone, and side-chain interactions. In particular, the preceding and following residue effects on amino-acid backbone conformational propensities are revealed and directly compared with previous works on either short peptides or empirical chemical shift database. (C) 2014 Wiley Periodicals, Inc.