The small GTPase Ras plays an important role in intracellular signal transduction and functions as a molecular switch. In this study, we used a photoresponsive protein as the molecular regulatory device to photoregulate Ras GTPase activity. Photo zipper (PZ), a variant of the photoresponsive protein Aureochrome1 developed by Hisatomi et al. (1-9) was incorporated into the C-terminus of Ras as a fusion protein. The three constructs of the Ras-PZ fusion protein had spacers of different lengths between Ras and PZ. They were designed using an Escherichia coli expression system. The Ras-PZ fusion proteins exhibited photoisomerization upon blue light irradiation and in the dark. Ras-PZ dimerized upon light irradiation. Moreover, Ras GTPase activity, which is accelerated by the Ras regulators guanine nucleotide exchange factors and GTPase-activating proteins, is controlled by photoisomerization. It has been suggested that light-responsive proteins are applicable to the photoswitching of the enzymatic activity of small GTPases as photoregulatory molecular devices.

中文翻译：

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与光响应蛋白融合的小 GTPase Ras 的光控制

小GTP酶Ras在细胞内信号转导中发挥着重要作用，并起到分子开关的作用。在本研究中，我们使用光响应蛋白作为分子调节装置来光调节 Ras GTPase 活性。Photo zipper (PZ) 是由 Hisatomi 等人开发的光响应蛋白 Aureochrome1 的变体。(1-9) 作为融合蛋白掺入 Ras 的 C 末端。Ras-PZ融合蛋白的三种构建体在Ras和PZ之间具有不同长度的间隔区。它们是使用大肠杆菌表达系统设计的。Ras-PZ 融合蛋白在蓝光照射和黑暗中表现出光致异构化。Ras-PZ 在光照射下二聚化。此外，Ras GTPase 活性由 Ras 调节剂鸟嘌呤核苷酸交换因子和 GTPase 激活蛋白加速，并受到光异构化的控制。有人建议，光响应蛋白可作为光调节分子装置应用于小 GTP 酶活性的光开关。