Liu Tao, Qi Ruibing, Feng Wanshi, Li Zhuohao, Zhong Zerun, Bai Chuan
Department of Pathogen Biology and Biosecurity, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.
Institute of Human Virology, Guangzhou, China.
Front Cell Dev Biol. 2025 Aug 20;13:1629762. doi: 10.3389/fcell.2025.1629762. eCollection 2025.
Electrophilic compounds from natural products (NPs) and metabolites can covalently modify the cysteines of target proteins to induce biological activities. To facilitate the discovery of novel NPs and metabolites, chemical probes with various thiol groups-mimicking the reactivity of cysteine-have been developed. These probes are designed to react with electrophilic groups of NPs and metabolites in an electrophilic addition mechanism, with the resulting adducts having molecular masses which equal to the sum of the probe and the target compound. This principle has been fundamental to analyzing mass spectrometry (MS) data and calculating the exact molecular weights of the target compound. In this study, we report a phenol thiol probe initially designed to mimic cysteine reacts with Mollugin and other structurally related NPs in an electrophilic free radical addition mechanism, and thus leads to the incorporation of not only the thiol probe but also a hydroxyl group in the adducts. Our results demonstrate that the phenol thiol group of the probe cannot always represent the thiol in cysteine to discover novel NPs or metabolites that can covalently modify cysteines.
天然产物（NPs）和代谢产物中的亲电化合物可共价修饰靶蛋白的半胱氨酸以诱导生物活性。为了促进新型NPs和代谢产物的发现，已开发出具有各种模仿半胱氨酸反应性的硫醇基团的化学探针。这些探针设计为以亲电加成机制与NPs和代谢产物的亲电基团反应，生成的加合物的分子量等于探针和靶化合物的分子量之和。这一原理对于分析质谱（MS）数据和计算靶化合物的精确分子量至关重要。在本研究中，我们报告了一种最初设计用于模仿半胱氨酸的酚硫醇探针，它以亲电自由基加成机制与莫鲁金和其他结构相关的NPs反应，从而导致加合物中不仅掺入了硫醇探针，还掺入了一个羟基。我们的结果表明，该探针的酚硫醇基团不能总是代表半胱氨酸中的硫醇来发现可共价修饰半胱氨酸的新型NPs或代谢产物。
