Contributions of the C-terminal domain to poly(A)-specific ribonuclease (PARN) stability and self-association.
Contributions of the C-terminal domain to poly(A)-specific ribonuclease (PARN) stability and self-association.
复制标题
C 末端结构域对聚腺苷酸特异性核糖核酸酶 (PARN) 稳定性和自缔合的贡献。
DOI：
10.1016/j.bbrep.2019.100626
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Yan Yong-Bin
中科院分区：
文献类型：
--
作者：
He Guang-Jun;Yan Yong-Bin
多聚腺苷酸特异性核糖核酸酶（PARN）催化mRNA多聚腺苷酸尾的降解，调节高等真核细胞的翻译效率和mRNA降解。全长PARN是一个多结构域蛋白，包含催化核酸酶结构域、R3H结构域、RRM结构域和C末端固有非结构域（CTD）。三个结构良好的RNA结合结构域的作用已被广泛研究，而对CTD知之甚少。在本研究中，CTD对PARN的稳定性和聚集效力的影响进行了研究，通过比较全长PARN与两个缺乏CTD的N端片段的热失活和变性行为。我们的研究结果表明，K+诱导额外的规则二级结构和增强对热诱导失活，解折叠和聚集的PARN稳定性。CTD阻止PARN的热失活，但促进热聚集，在远低于失活和解折叠所需的温度下开始。热转变过程中色氨酸荧光的蓝移表明，热处理诱导的结构域组织的重排。CTD增强了K+的稳定作用，说明CTD的作用主要是通过静电作用实现的。这些结果表明，CTD可能与分子的主体动态相互作用，CTD的释放通过静电相互作用促进自缔合。
Poly(A)-specific ribonuclease (PARN) catalyzes the degradation of mRNA poly(A) tail to regulate translation efficiency and mRNA decay in higher eukaryotic cells. The full-length PARN is a multi-domain protein containing the catalytic nuclease domain, the R3H domain, the RRM domain and the C-terminal intrinsically unstructured domain (CTD). The roles of the three well-structured RNA-binding domains have been extensively studied, while little is known about CTD. In this research, the impact of CTD on PARN stability and aggregatory potency was studied by comparing the thermal inactivation and denaturation behaviors of full-length PARN with two N-terminal fragments lacking CTD. Our results showed that K+induced additional regular secondary structures and enhanced PARN stability against heat-induced inactivation, unfolding and aggregation. CTD prevented PARN from thermal inactivation but promoted thermal aggregation to initiate at a temperature much lower than that required for inactivation and unfolding. Blue-shift of Trp fluorescence during thermal transitions suggested that heat treatment induced rearrangements of domain organizations. CTD amplified the stabilizing effect of K+, implying the roles of CTD was mainly achieved by electrostatic interactions. These results suggested that CTD might dynamically interact with the main body of the molecule and release of CTD promoted self-association via electrostatic interactions.