Rotamer Modelling of Cu(II) Spin Labels Based on the Double-Histidine Motif
Rotamer Modelling of Cu(II) Spin Labels Based on the Double-Histidine Motif
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DOI：
10.1007/s00723-018-1052-8
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发表时间：
2018-11-01
影响因子：
1
通讯作者：
Jeschke, Gunnar
中科院分区：
文献类型：
--
作者：
Ghosh, Shreya;Saxena, Sunil;Jeschke, Gunnar
连接到蛋白质链的两个残基上的自旋标记比连接到单个残基上的自旋标记具有更小的构象灵活性，因此导致未配对电子的空间分布更窄。因为它结合了精确定位未配对电子的优点和与更常见的基于半胱氨酸的标记正交的标记方案。在这里，我们介绍了一种方法，在硅自旋标记的蛋白质的dHis基序和Cu 2+复合物的亚氨基二乙酸或氨三乙酸。我们讨论了一个计算机化的扫描原生组氨酸对，可能倾向于结合这样的Cu 2+复合物和自旋标记位点对扫描，可以识别合适的双突变体标记。两个Cu 2+标签之间的预测距离分布进行比较，实验距离分布。我们还测试的假设，弹性网络建模的构象转换与铜2 +-dHis标签可以提供更准确的结构模型比氮氧标签。
Spin labels attached to two residues of a protein chain have less conformational flexibility than those attached to a single residue and thus lead to a narrower spatial distribution of the unpaired electron. The case of Cu2+ labels based on the double-histidine (dHis) motif is of particular interest, as it combines the advantage of precise localization of the unpaired electron with a labelling scheme orthogonal to the more common cysteine-based labelling. Here, we introduce an approach for in silico spin labelling of a protein by dHis motifs and Cu2+ complexes of iminodiacetic acid or nitrilotriacetic acid. We discuss a computerized scan for native histidine pairs that might be prone to bind such Cu2+ complexes and spin-labelling site pair scans that can identify suitable double mutants for labelling. Predicted distance distributions between two Cu2+ labels are compared to experimental distance distributions. We also test the hypothesis that elastic network modelling of conformational transitions with Cu2+-dHis labels can provide more accurate structural models than with nitroxide labels.