Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96, Gothenburg, Sweden.
Department of Chemistry, Umeå University, 90187, Umeå, Sweden.
Biometals. 2019 Dec;32(6):875-885. doi: 10.1007/s10534-019-00219-y. Epub 2019 Oct 9.
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.
威尔逊病（WD）是由 ATP7B 基因突变引起的，ATP7B 是一种铜转运蛋白，可调节细胞内的铜水平。大量错义突变被报道可导致 WD，但基因型-表型相关性尚未建立。由于 WD 的基因筛查可能在未来成为现实，因此了解单个突变如何影响 ATP7B 功能非常重要，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，我们研究了 ATP7B 金属结合域 5 和 6 中的四个拟议的 WD 致病错义突变。这四个变体中的三个在传统的酵母测定中显示出 ATP7B 铜转运能力降低。为了在原子水平上探测突变诱导的结构动态效应，我们进行了分子动力学模拟（每个变体 1.5μs 的模拟时间）。通过比较有和没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。大多数突变引入了远距离效应，导致铜结合环的动力学增加。综上所述，突变诱导的结构动力学的远程改变为铜转运能力降低提供了合理的依据。
