Department of Chemistry and Biochemistry, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080-3021, USA.
Department of Chemistry, Wayne State University, 42 W. Warren Ave., Detroit, MI 48202, USA.
Angew Chem Int Ed Engl. 2023 Jun 26;62(26):e202302304. doi: 10.1002/anie.202302304. Epub 2023 May 16.
Detection of anions in complex aqueous media is a fundamental challenge with practical utility that can be addressed by supramolecular chemistry. Biomolecular hosts such as proteins can be used and adapted as an alternative to synthetic hosts. Here, we report how the mutagenesis of the β-bulge residues (D137 and W138) in mNeonGreen, a bright, monomeric fluorescent protein, unlocks and tunes the anion preference at physiological pH for sulfate, resulting in the turn-off sensor SulfOFF-1. This unprecedented sensing arises from an enhancement in the kinetics of binding, largely driven by position 138. In line with these data, molecular dynamics (MD) simulations capture how the coordinated entry and gating of sulfate into the β-barrel is eliminated upon mutagenesis to facilitate binding and fluorescence quenching.
在复杂的水介质中检测阴离子具有实际应用的重要意义，可以通过超分子化学来解决。生物分子主体（如蛋白质）可以被用作合成主体的替代物，并进行适当的改造。在这里，我们报告了如何通过突变 mNeonGreen（一种明亮的单体荧光蛋白）中的β-凸起残基（D137 和 W138），在生理 pH 值下解锁并调整对硫酸盐的阴离子偏好性，从而产生关闭型传感器 SulfOFF-1。这种前所未有的传感源于结合动力学的增强，主要由位置 138 驱动。与这些数据一致，分子动力学（MD）模拟捕捉到，突变后，硫酸盐进入β-桶的协调进入和门控是如何被消除的，从而促进了结合和荧光猝灭。
