Shen Di, Zhao Qun, Zhang Huaiyue, Wu Ci, Jin Hao, Guo Kun, Sun Rui, Guo Hengke, Zhao Qi, Feng Huan, Dong Xuepeng, Gao Zhenming, Zhang Lihua, Liu Yu
State Key Laboratory of Medical Proteomics, National Chromatographic Research & Analysis Center, Chinese Academy of Sciences Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Proc Natl Acad Sci U S A. 2025 Apr 22;122(16):e2420861122. doi: 10.1073/pnas.2420861122. Epub 2025 Apr 16.
Most bioorthogonal photouncaging reactions preferentially occur in polar environments to accommodate biological applications in the aqueous cellular milieu. However, they are not precisely designed to chemically adapt to the diverse microenvironments of the cell. Herein, we report a hydrophobic photouncaging reaction with tailored photolytic kinetics toward solvent polarity. Structural modulations of the aminobenzoquinone-based photocage reveal the impact of cyclic ring size, steric substituent, and electronic substituent on the individual uncaging kinetics ( and ) and polarity preference (/). Rational incorporation of optimized moieties leads to up to 20.2-fold nonpolar kinetic selectivity (/). Further photochemical spectroscopic characterizations and theoretical calculations together uncover the mechanism underlying the polarity-dependent uncaging kinetics. The uncaged ortho-quinone methide product bears covalent reactivity toward diverse nucleophiles of a protein revealed by tandem mass spectrometry. Finally, we demonstrate the application of such lipophilic photouncaging chemistry toward selective labeling and profiling of proteins in proximity to lipid droplets inside human fatty liver tissues. Together, this work studies the solvent polarity effects of a photouncaging reaction and chemically adapts it toward suborganelle-targeted protein proximity labeling and profiling.
大多数生物正交光解笼反应优先在极性环境中发生，以适应在水性细胞环境中的生物学应用。然而，它们并非精确设计用于化学适应细胞的多种微环境。在此，我们报道了一种对溶剂极性具有定制光解动力学的疏水光解笼反应。基于氨基苯醌的光笼的结构调制揭示了环大小、空间取代基和电子取代基对单个解笼动力学（kₒₚₑₙ和kₚₒₗₐᵣ）以及极性偏好（kₙₒₙₚₒₗₐᵣ/kₚₒₗₐᵣ）的影响。合理引入优化的基团可导致高达20.2倍的非极性动力学选择性（kₙₒₙₚₒₗₐᵣ/kₚₒₗₐᵣ）。进一步的光化学光谱表征和理论计算共同揭示了极性依赖的解笼动力学的潜在机制。串联质谱显示，解笼后的邻醌甲基化物产物对蛋白质的多种亲核试剂具有共价反应性。最后，我们展示了这种亲脂性光解笼化学在对人脂肪肝组织内脂滴附近的蛋白质进行选择性标记和分析方面的应用。总之，这项工作研究了光解笼反应的溶剂极性效应，并对其进行化学调整以用于亚细胞器靶向的蛋白质邻近标记和分析。
