2-Azo-, 2-diazocine-thiazols and 2-azo-imidazoles as photoswitchable kinase inhibitors: limitations and pitfalls of the photoswitchable inhibitor approach
2-Azo-, 2-diazocine-thiazols and 2-azo-imidazoles as photoswitchable kinase inhibitors: limitations and pitfalls of the photoswitchable inhibitor approach
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DOI：
10.1039/c9pp00010k
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发表时间：
2019-06-01
影响因子：
3.1
通讯作者：
Herges, Rainer
中科院分区：
文献类型：
--
作者：
Schehr, Miriam;Ianes, Chiara;Herges, Rainer
在生物药理学中，包括偶氮苯或其他二芳基偶氮部分的光可切换化合物表现出针对靶蛋白的生物活性，通常为细长的E-构型，而相当庞大的Z-构型通常是不太有效的。本文报道了以p38 a MAPK和CK 1d为靶点的新型光开关激酶抑制剂的设计、合成和光化学/抑制特性。使用充分表征的抑制剂支架连接芳基偶氮和二氮杂环辛部分。然而，当在常用的体外激酶测定中测试分离的异构体或异构体的光稳态（PSS）时，仅观察到活性的微小差异。配体结合的p38 a MAPK和CK 1d复合物的X-射线分析显示，相对于这两种异构体的蛋白质的动态构象适应。更重要的是，观察到偶氮基团不可逆地还原为相应的肼。独立的实验表明，还原剂，如DTT（二硫苏糖醇）和GSH（谷胱甘肽），通常用于蛋白质稳定的生物测定是负责。误差的另外两个来源是E-Z转换效率的浓度依赖性和由于测试期间不完全排除光而导致的伪影。我们的研究结果也可能适用于一些以前研究的偶氮苯为基础的光开关抑制剂。
In photopharmacology, photoswitchable compounds including azobenzene or other diarylazo moieties exhibit bioactivity against a target protein typically in the slender E-configuration, whereas the rather bulky Z-configuration usually is pharmacologically less potent. Herein we report the design, synthesis and photochemical/inhibitory characterization of new photoswitchable kinase inhibitors targeting p38a MAPK and CK1d. A well characterized inhibitor scaffold was used to attach arylazo-and diazocine moieties. When the isolated isomers, or the photostationary state (PSS) of isomers, were tested in commonly used in vitro kinase assays, however, only small differences in activity were observed. X-ray analyses of ligandbound p38a MAPK and CK1d complexes revealed dynamic conformational adaptations of the protein with respect to both isomers. More importantly, irreversible reduction of the azo group to the corresponding hydrazine was observed. Independent experiments revealed that reducing agents such as DTT (dithiothreitol) and GSH (glutathione) that are typically used for protein stabilization in biological assays were responsible. Two further sources of error are the concentration dependence of the E-Z-switching efficiency and artefacts due to incomplete exclusion of light during testing. Our findings may also apply to a number of previously investigated azobenzene-based photoswitchable inhibitors.