Institute of Molecular and Clinical Medicine, Kunming Medical University, Kunming, China; National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
Hong Shan
iHuman Institute, ShanghaiTech University, Shanghai, China
Yanping Zhu
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
Shunlin Hu
College of Veterinary Medicine, Yangzhou University, Yangzhou, China
Ling Xue
College of Veterinary Medicine, Yangzhou University, Yangzhou, China
Yong Chen
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
Wei Ding
Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
Tongxin Niu
Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
Jian Gu
College of Veterinary Medicine, Yangzhou University, Yangzhou, China
Songying Ouyang
The Key Laboratory of Innate Immune Biology of Fujian Province, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, China; Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, College of Life Sciences, Fujian Normal University, Fuzhou, China
Qing-Tao Shen
iHuman Institute, ShanghaiTech University, Shanghai, China
Institute of Molecular and Clinical Medicine, Kunming Medical University, Kunming, China; National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; iHuman Institute, ShanghaiTech University, Shanghai, China
Non-segmented negative-strand RNA viruses, such as measles, ebola and Newcastle disease viruses (NDV), encapsidate viral genomic RNAs into helical nucleocapsids, which serve as the template for viral replication and transcription. Here, the clam-shaped nucleocapsid structure, where the NDV viral genome is sequestered, was determined at 4.8 Å resolution by cryo-electron microscopy. The clam-shaped structure is composed of two single-turn spirals packed in a back-to-back mode. This tightly packed structure functions as a seed for the assembly of a nucleocapsid from both directions, facilitating the growth of double-headed filaments with two separate RNA strings inside. Disruption of this structure by mutations in its loop interface yielded a single-headed unfunctional filament.
