Modelling of protein structures based on backbone chemical shifts, using programs such as CS-ROSETTA, is becoming increasingly popular, especially for systems where few restraints are available or where homologous structures are already known. While the reliability of CS-ROSETTA calculations can be improved by incorporation of some additional backbone NMR data such as those afforded by residual dipolar couplings or minimal NOE data sets involving backbone amide protons, the sidechain conformations are largely modelled by statistical energy terms. Here, we present a simple method based on methyl residual dipolar couplings that can be used to determine the rotameric state of the threefold symmetry axis of methyl groups that occupy a single rotamer, determine rotameric distributions, and identify regions of high flexibility. The method is demonstrated for methyl side chains of a deletion variant of the human chaperone DNAJB6b.

中文翻译：

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使用甲基1H-13C残留偶极偶合确定CS-ROSETTA模型中的甲基侧链构象。

使用诸如CS-ROSETTA之类的程序基于主链化学位移的蛋白质结构建模正变得越来越流行，特别是对于几乎没有约束条件或已知同源结构的系统。虽然CS-ROSETTA计算的可靠性可以通过合并一些其他的主链NMR数据来提高，例如通过残留的偶极偶合或涉及主链酰胺质子的最小NOE数据集所提供的数据，但侧链构象很大程度上是通过统计能项建模的。在这里，我们提出了一种基于甲基残留偶极偶合的简单方法，该方法可用于确定占据单个旋转异构体的甲基的三重对称轴的旋转状态，确定旋转异构分布，并确定具有高柔韧性的区域。