Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH-Hönggerberg, 8093, Zurich, Switzerland.
J Biomol NMR. 2010 Feb;46(2):135-47. doi: 10.1007/s10858-009-9387-y. Epub 2009 Nov 11.
The measurements of cross-correlated relaxation rates between H(N)-N and C(beta)-C(gamma) intraresidual and sequential dipolar interactions is demonstrated in ASN, ASP and aromatic residues. The experiment can be used for deuterated samples and no additional knowledge such as Karplus parametrizations is required for the analysis. The data constitutes a new type of information since no other method relates the C(beta)-C(gamma) bond to H(N)-N. Using this method the dominant populations of rotamer states of chi 1 can be readily cross checked provided that phi or psi are known. In addition, dynamics on all timescales can be probed. As opposed to standard dynamics analysis of isolated bonds, the presented observables depend on relative dynamics with an interesting prospect to analyze correlated fluctuations of the two torsion angles phi or psi with chi 1. Experimental rates are compared to single conformer and ensemble representations of GB3 and ubiquitin. In particular, it is found that the recently published ubiquitin ensemble 2k39 improves the agreement obtained for 1UBQ. In general, however, input data restricting ASX and aromatic side chains in structure calculation is sparse highlighting the need for new NMR observables.
在 ASN、ASP 和芳香族残基中，演示了 H(N)-N 和 C(beta)-C(gamma) 内残基和顺序偶极相互作用之间交叉相关弛豫率的测量。该实验可用于氘代样品，并且在分析中不需要 Karplus 参数化等其他知识。由于没有其他方法将 C(beta)-C(gamma) 键与 H(N)-N 相关联，因此这些数据代表了一种新的信息类型。使用这种方法，只要知道 phi 或 psi，就可以很容易地交叉检查 chi1 的构象状态的主要分布。此外，还可以探测所有时间尺度的动力学。与孤立键的标准动力学分析相反，所提出的可观测量取决于相对动力学，这为分析两个扭转角 phi 或 psi 与 chi1 的相关波动提供了有趣的前景。实验速率与 GB3 和泛素的单构象和集合表示进行了比较。特别是，发现最近发表的泛素集合 2k39 提高了对 1UBQ 的拟合程度。然而，一般来说，限制结构计算中 ASX 和芳香族侧链的输入数据是稀疏的，这突出了对新 NMR 可观测物的需求。
