Cryo-EM reveals mechanisms of natural RNA multivalency
Liu Wang, Jiahao Xie, Tao Gong, Hao Wu, You‐Liang Tu, Xin Peng, Sitong Shang, Xinyu Jia, Haiyun Ma, Jian Zou, Sheng Xu, Xin Zheng, Dong Zhang, Yang Liu, Chong Zhang, Yongbo Luo, Zirui Huang, Bin Shao, Binwu Ying, Yu Cheng, Yingqiang Guo, Ying Lai, Dingming Huang, Jianquan Liu, Yuquan Wei, Siqi Sun, Xuedong Zhou, Zhaoming Su
Abstract
Homo-oligomerization of biological macromolecules leads to functional assemblies that are critical to understanding various cellular processes. However, RNA quaternary structures have rarely been reported. Comparative genomics analysis has identified RNA families containing hundreds of sequences that adopt conserved secondary structures and likely fold into complex three-dimensional structures. In this study, we used cryo-electron microscopy (cryo-EM) to determine structures from four RNA families, including ARRPOF and OLE forming dimers and ROOL and GOLLD forming hexameric, octameric, and dodecameric nanostructures, at 2.6- to 4.6-angstrom resolutions. These homo-oligomeric assemblies reveal a plethora of structural motifs that contribute to RNA multivalency, including kissing-loop, palindromic base-pairing, A-stacking, metal ion coordination, pseudoknot, and minor-groove interactions. These results provide the molecular basis of intermolecular interactions driving RNA multivalency with potential functional relevance.