Photoclick chemistry represents an integration of photo- and click chemistry, enabling spatiotemporal control, high selectivity, and efficient conjugation. Photo-induced defluorination acyl fluoride exchange (photo-DAFEx), as a novel photoclick reaction, has emerged as a promising tool for the flourishing field of photoaffinity labeling (PAL) for drug discovery and the exploration of protein interactions. Currently, the first-generation photo-DAFEx reaction relies on the photo-defluorination of a monocyclic m-trifluoromethylaniline, and consequently the excitation wavelength (λ_ex.) falls within the UV-B band (311 nm), limiting its widespread applications. Therefore, there is a high demand for the discovery of innovative cores that can expedite visible-light-induced photo-DAFEx reactions and for the exploration of their crosslinking capabilities. Herein, we report that the combination of phenoxazine chromophores with dialkylated amine auxochromes expands the excitation wavelength (λ_ex.) of the photo-DAFEx reacion into the visible region (405 nm), enabling the multifunctional design of photoaffinity probes for in situ identification of drug–target interactions. By employing the phenoxazine-based photo-DAFEx reagent, we successfully developed potent PAL probes targeting hCA-II and BRD4, which can be activated with controllability using a 405 nm LED, thereby underscoring the potential of photo-DAFEx in advancing our understanding of protein–ligand interactions.

中文翻译：

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基于吩噁嗪发色团的可见光响应脱氟-酰氟交换光click labeling


Photoclick 化学代表了 photo-click 化学和click化学的集成，可实现时空控制、高选择性和高效偶联。光诱导脱氟酰氟交换 （photo-DAFEx） 作为一种新型的光点击反应，已成为用于药物发现和蛋白质相互作用探索的光亲和标记 （PAL） 蓬勃发展领域的一种有前途的工具。目前，第一代光-DAFEx 反应依赖于单环间三氟甲基苯胺的光脱氟反应，因此激发波长 （λ_ex.） 落在 UV-B 波段 （311 nm） 内，限制了其广泛应用。因此，对于发现可以加速可见光诱导的光 DAFEx 反应的创新核心以及探索它们的交联能力的需求很高。在此，我们报道了吩噁嗪发色团与二烷基化胺辅助色素的组合将光-DAFEx 反应的激发波长 （λ_ex.） 扩展到可见区域 （405 nm），从而能够实现光亲和探针的多功能设计，用于原位鉴定药物-靶标相互作用。通过使用基于吩噁嗪的光 DAFEx 试剂，我们成功开发了靶向 hCA-II 和 BRD4 的强效 PAL 探针，可以使用 405 nm LED 可控激活，从而强调了光 DAFEx 在推进我们对蛋白质-配体相互作用的理解方面的潜力。