Departments of Chemistry, and ‡Physics, and §the Center for Theoretical Biological Physics, Rice University , Houston, Texas 77030, United States.
J Am Chem Soc. 2018 Jan 31;140(4):1203-1206. doi: 10.1021/jacs.7b10851. Epub 2018 Jan 22.
The rational design of genetically encoded fluorescent biosensors, which can detect rearrangements of target proteins via interdomain allostery, is hindered by the absence of mechanistic understanding of the underlying photophysics. Here, we focus on the modulation of fluorescence by mechanical perturbation in a popular biological probe: enhanced Green Fluorescent Protein (eGFP). Using a combination of molecular dynamics (MD) simulations and quantum chemistry, and a set of physically motivated assumptions, we construct a map of fluorescence quantum yield as a function of a 2D electric field imposed by the protein environment on the fluorophore. This map is transferable between Tsien's Class 2 GFP's, and it allows one to estimate the shifts in fluorescence intensity due to mechanical perturbations directly from MD simulations. We use it in combination with steered MD simulations to put forward a hypothesis for the mechanism of a genetically encoded voltage probe (ArcLight) whose mechanism is currently under debate.
遗传编码荧光生物传感器的合理设计，可以通过结构域间变构来检测靶蛋白的重排，但由于缺乏对潜在光物理机制的理解而受到阻碍。在这里，我们专注于机械扰动对一种流行的生物探针——增强型绿色荧光蛋白（eGFP）荧光的调制。我们使用分子动力学（MD）模拟和量子化学的组合，以及一组基于物理的假设，构建了一个荧光量子产率与蛋白质环境对荧光团施加的二维电场之间的映射图。该图谱在 Tsien 的 Class 2 GFP 之间是可转移的，它允许人们直接从 MD 模拟中估计由于机械扰动引起的荧光强度的位移。我们将其与导向 MD 模拟结合使用，提出了一种遗传编码电压探针（ArcLight）的机制假说，其机制目前仍存在争议。
