Wilson disease (WD) is caused by mutations in the gene for ATP7B, a copper transport protein that regulates copper levels in cells. A large number of missense mutations have been reported to cause WD but genotype-phenotype correlations are not yet established. Since genetic screening for WD may become reality in the future, it is important to know how individual mutations affect ATP7B function, with the ultimate goal to predict pathophysiology of the disease. To begin to assess mechanisms of dysfunction, we investigated four proposed WD-causing missense mutations in metal-binding domains 5 and 6 of ATP7B. Three of the four variants showed reduced ATP7B copper transport ability in a traditional yeast assay. To probe mutation-induced structural dynamic effects at the atomic level, molecular dynamics simulations (1.5 μs simulation time for each variant) were employed. Upon comparing individual metal-binding domains with and without mutations, we identified distinct differences in structural dynamics via root-mean square fluctuation and secondary structure content analyses. Most mutations introduced distant effects resulting in increased dynamics in the copper-binding loop. Taken together, mutation-induced long-range alterations in structural dynamics provide a rationale for reduced copper transport ability.

中文翻译：

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ATP7B中的Wilson病错义突变影响金属结合域的结构动力学。

威尔逊病（WD）是由ATP7B的基因突变引起的，ATP7B是一种铜转运蛋白，调节细胞中的铜水平。据报道，大量的错义突变会导致WD，但尚未建立基因型与表型的相关性。由于对WD进行基因筛查可能在将来成为现实，因此重要的是要知道单个突变如何影响ATP7B的功能，其最终目的是预测疾病的病理生理学。为了开始评估功能障碍的机制，我们调查了ATP7B的金属结合域5和6中的四个拟议的WD致错义突变。四个变体中的三个在传统酵母分析中显示出降低的ATP7B铜转运能力。为了在原子水平上探究突变引起的结构动力学效应，分子动力学模拟（1。每个变体的仿真时间为5μs。通过比较具有和不具有突变的单个金属结合域，我们通过均方根波动和二级结构含量分析确定了结构动力学的明显差异。大多数突变引入了遥远的影响，从而导致铜结合环的动力学增加。综上所述，突变诱发的结构动力学的长期变化为降低铜的运输能力提供了理论依据。