Abstract：
Cryptochromes are a ubiquitously occurring class of photoreceptors. Together with photolyases, they form the Photolyase Cryptochrome Superfamily (PCSf) by sharing a common protein architecture and binding mode of the FAD chromophore. Despite these similarities, PCSf members exert different functions. Photolyases repair UV-induced DNA damage by photocatalytically driven electron transfer between FADH¯ and the DNA lesion, whereas cryptochromes are light-dependent signaling molecules and trigger various biological processes by photoconversion of their FAD redox and charge states. Given that most cryptochromes possess a C-terminal extension (CTE) of varying length, the functions of their CTE have not yet been fully elucidated and are hence highly debated. In this study, the role of the CTE was investigated for a novel subclass of the PCSf, the CryP-like cryptochromes, by hydrogen/deuterium exchange and mass-spectrometric analysis. Striking differences in the relative deuterium uptake were observed in different redox states of CryP from the diatom Phaeodactylum tricornutum. Based on these measurements we propose a model for light-triggered conformational changes in CryP-like cryptochromes that differs from other known cryptochrome families like the insect or plant cryptochromes.
摘要：
隐色素是一类普遍存在的光感受器。连同光解酶，它们通过共享FAD发色团的共同蛋白质结构和结合模式来形成光解酶密码超家族（PCSf）。尽管有这些相似之处,PCSf成员发挥不同的功能。光解酶通过光催化驱动的FADH和DNA损伤之间的电子转移来修复紫外线诱导的DNA损伤，而隐色素是光依赖性信号分子，并通过其FAD氧化还原和电荷状态的光转换触发各种生物过程。鉴于大多数隐色素具有不同长度的C端扩展（CTE），其CTE的功能尚未完全阐明，因此存在激烈争议。在这项研究中,CTE的作用被研究为PCSf的一个新的亚类，类似CryP的隐色素，通过氢/氘交换和质谱分析。在硅藻Phaeodactylumricornutum的CryP的不同氧化还原状态下，观察到相对氘吸收的惊人差异。基于这些测量，我们提出了一种用于CryP样隐色素中光触发的构象变化的模型，该模型不同于其他已知的隐色素家族，例如昆虫或植物隐色素。
