Azobenzene analogues of the tubulin polymerisation inhibitor combretastatin A4 (PSTs) were previously developed to optically control microtubule dynamics in living systems, with subsecond response time and single-cell spatial precision, by reversible in situ photoswitching of their bioactivity with near-UV/visible light. First-generation PSTs were sufficiently potent and photoswitchable for use in live cells and embryos. However, the link between their seconds-scale and hours-scale bioactivity remained untested. Furthermore, the scope for modifications to tune their photo-structure-activity-relationship or expand their function was unknown. Here, we used large-field-of-view, long-term tandem photoswitching/microscopy to reveal the temporal onset of cytostatic effects. We then synthesised a panel of novel PSTs exploring structural variations that tune photoresponse wavelengths and lipophilicity, identifying promising blue-shifted analogues that are better-compatible with GFP/YFP imaging. Taken together, these results can guide new design and applications for photoswitchable microtubule inhibitors. We also identified tolerated sites for linkers to attach functional cargos; and we tested fluorophores, aiming at RET isomerisation or reporter probes. Instead we found that these antennas greatly enhance long-wavelength single-photon photoisomerisation, by an as-yet un-explored mechanism, that can now drive general progress towards near-quantitative long-wavelength photoswitching of photopharmaceuticals in living systems, with minimal molecular redesign and broad scope.

中文翻译：

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光开关偶氮苯微管蛋白抑制抗有丝分裂的光SAR研究确定了近定量光控制的通用方法


微管蛋白聚合抑制剂考布他汀 A4 (PST) 的偶氮苯类似物先前被开发用于光学控制生命系统中的微管动力学，通过近紫外/可见光对其生物活性进行可逆原位光切换，具有亚秒级响应时间和单细胞空间精度。第一代 PST 足够有效且可光切换，可用于活细胞和胚胎。然而，它们的秒级和小时级生物活性之间的联系尚未经过测试。此外，调整其光结构活动关系或扩展其功能的修改范围尚不清楚。在这里，我们使用大视场、长期串联光开关/显微镜来揭示细胞抑制效应的时间发生。然后，我们合成了一组新型 PST，探索调节光响应波长和亲脂性的结构变化，识别出与 GFP/YFP 成像更好兼容的有前途的蓝移类似物。总而言之，这些结果可以指导光开关微管抑制剂的新设计和应用。我们还确定了连接器连接功能性货物的耐受位点；我们测试了针对 RET 异构化或报告探针的荧光团。相反，我们发现这些天线通过一种尚未探索的机制极大地增强了长波长单光子光异构化，现在可以推动生命系统中光药物的近定量长波长光切换的总体进展，并且只需最少的分子重新设计且范围广泛。