The application of peptide stapling using photoswitchable linkers has gained notable interest for potential therapeutic applications. However, many existing methodologies of photoswitching still rely on the use of tissue-damaging and weakly skin-penetrating UV light. Herein, we describe the development of a tetra-ortho-chloro azobenzene linker that was successfully used for cysteine-selective peptide stapling via S_NAr. This linker facilitates precise photocontrol of peptide structure via trans to cis isomerisation under red light irradiation. As a proof-of-concept, we applied the developed peptide stapling platform to a modified PMI peptide, targeting the inhibition of MDM2/p53 protein–protein interaction (PPI). Biophysical characterisation of the photoswitchable peptide by competitive fluorescence polarisation showed a significant difference in affinity between the trans and cis isomer for the p53-interacting domain of the human MDM2. Remarkably, the cis isomer displayed a >240-fold higher potency. To the best of our knowledge, this is the highest reported difference in binding affinity between isoforms of a photoswitchable therapeutic peptide. Overall, our findings demonstrate the potential of this novel photoswitchable peptide stapling system for tuneable, selective modulation of PPIs via visible-light isomerisation with deeply-tissue penetrating red light.

中文翻译：

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红光调制邻氯偶氮苯光开关，用于通过芳香族取代进行肽装订

使用光开关连接器进行肽装订的应用在潜在的治疗应用中引起了人们的极大兴趣。然而，许多现有的光开关方法仍然依赖于使用组织损伤性和皮肤穿透性较弱的紫外线。在此，我们描述了四邻氯偶氮苯接头的开发，该接头已成功用于通过S _N Ar 进行半胱氨酸选择性肽装订。该接头在红光照射下通过反式异构化促进肽结构的精确光控制。作为概念验证，我们将开发的肽装订平台应用于修饰的 PMI 肽，旨在抑制 MDM2/p53 蛋白质-蛋白质相互作用 (PPI)。通过竞争性荧光偏振对光开关肽进行的生物物理表征表明，反式和顺式异构体对人 MDM2 的 p53 相互作用结构域的亲和力存在显着差异。值得注意的是，顺式异构体的效力高出 240 倍以上。据我们所知，这是光可切换治疗肽同工型之间结合亲和力差异最大的报道。总的来说，我们的研究结果证明了这种新型光开关肽缝合系统的潜力，可通过深组织穿透红光的可见光异构化来调节、选择性调节 PPI。