Structural insights into a novel functional dimer of Staphylococcus aureus RNase HII
Structural insights into a novel functional dimer of Staphylococcus aureus RNase HII
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金黄色葡萄球菌 RNase HII 新型功能二聚体的结构见解
DOI：
10.1016/j.bbrc.2018.07.026
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发表时间：
2018
影响因子：
3.1
通讯作者：
Zang Jianye
中科院分区：
文献类型：
--
作者：
Hang Tianrong;Zhang Xiaozhen;Wu Minhao;Wang Chengliang;Ling Shenglong;Xu Ling;Gong Qingguo;Tian Changlin;Zhang Xuan;Zang Jianye
RNA酶HII广泛存在于生物体中，在原核生物中作为单体发挥功能。我们确定了金黄色葡萄球菌RNase HII（Sa-RNase HII）的晶体结构，它显示出一种新的二聚体构象，每个单体的活性位点被另一个单体覆盖。小角X-射线散射和凝胶过滤分析证实，Sa-RNase HII在溶液中以同源二聚体的形式存在。酶分析显示，“自抑制”二聚体形式是催化活性的。此外，连续波电子顺磁共振实验澄清，SA-RNA酶HII二聚体经历了一个大的构象变化后，底物结合，但仍然是一个二聚体催化反应。我们的结构和生物化学研究确定了一种新的功能性二聚体的Sa-RNase HII具有独特的调节机制，其催化活性。
RNase HII exists ubiquitously in organisms and functions as a monomer in prokaryotes. We determined the crystal structure ofStaphylococcus aureusRNase HII (Sa-RNase HII), which displays a novel dimer conformation, with the active site of each monomer covered by the other one. Both small-angle X-ray scattering and gel-filtration analysis confirmed that Sa-RNase HII exists as a homodimer in solution. Enzymatic analysis revealed that the “self-inhibited” dimeric form is catalytically active. Furthermore, continuous-wave electron paramagnetic resonance experiments clarified that the Sa-RNase HII dimer undergoes a large conformational change upon substrate binding, but remains a dimer to catalyze the reaction. Our structural and biochemical studies identified a novel functional dimer of Sa-RNase HII with distinct regulation mechanism for its catalytic activity.