Department of Chemistry , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States.
J Am Chem Soc. 2019 Feb 20;141(7):2857-2861. doi: 10.1021/jacs.8b12155. Epub 2019 Feb 11.
Sensitive yet rapid methods for detection of rare earth elements (REEs), including lanthanides (Lns), would facilitate mining and recycling of these elements. Here we report a highly selective, genetically encoded fluorescent sensor for Lns, LaMP1, based on the recently characterized protein, lanmodulin. LaMP1 displays a 7-fold ratiometric response to all Lns, with apparent Ks of 10-50 pM but only weak response to other common divalent and trivalent metal ions. We use LaMP1 to demonstrate for the first time that a Ln-utilizing bacterium, Methylobacterium extorquens, selectively transports early Lns (La-Nd) into its cytosol, a surprising observation as the only Ln-proteins identified to date are periplasmic. Finally, we apply LaMP1 to suggest the existence of a Ln uptake system utilizing a secreted metal chelator, akin to siderophore-mediated Fe acquisition. LaMP1 not only sheds light on Ln biology but also may be a useful technology for detecting and quantifying REEs in environmental and industrial samples.
灵敏且快速的检测稀土元素（REEs）的方法，包括镧系元素（Lns），将有助于这些元素的开采和回收。在这里，我们报告了一种基于最近被描述的蛋白lanmodulin 的高度选择性的、遗传编码的荧光传感器，用于 Lns，LaMP1。LaMP1 对所有 Lns 均呈现 7 倍的比率响应，其表观 Ks 为 10-50 pM，但对其他常见的二价和三价金属离子仅有微弱的响应。我们首次使用 LaMP1 证明了一种利用镧系元素的细菌 Methylobacterium extorquens 将早期的镧系元素（La-Nd）选择性地转运到其细胞质中，这是一个令人惊讶的观察结果，因为迄今为止鉴定的唯一的镧系蛋白是周质的。最后，我们应用 LaMP1 表明存在一种利用分泌的金属螯合剂的镧系元素摄取系统，类似于铁载体介导的铁获取。LaMP1 不仅揭示了 Ln 生物学，而且可能是检测和量化环境和工业样品中 REEs 的有用技术。
