Development of Second-Generation Acyl Silane Photoaffinity Probes for Cellular Chemoproteomic Profiling

Deconvolution of the protein targets of hit compounds from phenotypic screens, often conducted in live cells, is critical for understanding mechanism of action and identifying potentially hazardous off-target interactions. While photoaffinity labeling and chemoproteomics are long-established approaches for discovering small-molecule-protein interactions in live cells, there are a relatively small number of photoaffinity labeling strategies that can be applied for chemoproteomic target identification studies. Recently, we reported a novel chemical framework for photoaffinity labeling based on the photo-Brook rearrangement of acyl silanes and demonstrated its ability, when appended to protein-targeting ligands, to label recombinant proteins. Here, we report the application of these probes to live cell photoaffinity workflows, demonstrate their complementarity to current state-of-the-art minimalist diazirine-based photoaffinity probes, and introduce a modular synthetic route to access acyl silane scaffolds with improved labeling properties.对表型筛选（phenotypic screens）所得命中化合物的蛋白靶点进行解卷积分析，此类筛选通常在活细胞中开展，这对于阐明化合物作用机制、识别潜在有害的脱靶相互作用至关重要。尽管光亲和标记（photoaffinity labeling）与化学蛋白质组学（chemoproteomics）是在活细胞中探究小分子-蛋白相互作用的经典方法，但可应用于化学蛋白质组学靶点鉴定研究的光亲和标记策略仍相对匮乏。近期，我们报道了一种基于酰硅烷光-布鲁克重排（photo-Brook rearrangement of acyl silanes）的新型光亲和标记化学骨架，并证实当其偶联至蛋白靶向配体时，可实现对重组蛋白的标记。本文报道了此类探针在活细胞光亲和标记实验流程中的应用，验证了其与当前主流的极简型双吖丙啶（diazirine）基光亲和标记探针的互补性，并介绍了一条模块化合成路线，用以制备具有更优标记性能的酰硅烷骨架。