1. Structure of Rift Valley Fever Virus RNA-Dependent RNA Polymerase
- Author
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Wei Ye, Wei Wu, Shaodong Dai, Zhongzhou Chen, Hong-Wei Wang, Manfeng Zhang, Hongyun Lu, Jia Wang, Xue Wang, Cuixia Hu, Jie Xu, Xiaofei Dong, Fanglin Zhang, and Xiaorong Li
- Subjects
Models, Molecular ,Chemical Phenomena ,Protein Conformation ,Recombinant Fusion Proteins ,viruses ,Amino Acid Motifs ,Immunology ,RNA-dependent RNA polymerase ,Biology ,Microbiology ,Genome ,Arbovirus ,Virus ,Viral Proteins ,chemistry.chemical_compound ,Protein structure ,Transcription (biology) ,Catalytic Domain ,Virology ,RNA polymerase ,medicine ,Protein Interaction Domains and Motifs ,Conserved Sequence ,chemistry.chemical_classification ,Structure and Assembly ,Cryoelectron Microscopy ,RNA-Dependent RNA Polymerase ,Rift Valley fever virus ,medicine.disease ,Enzyme ,chemistry ,Insect Science - Abstract
Rift Valley fever virus (RVFV) belongs to the order Bunyavirales and is the type species of genus Phlebovirus, which accounts for over 50% of family Phenuiviridae species. RVFV is mosquito-borne and causes severe diseases in both humans and livestock, and consists of three segments (S, M, L) in the genome. The L segment encodes an RNA-dependent RNA polymerase (RdRp, L protein) that is responsible for facilitating the replication and transcription of the virus. It is essential for the virus and has multiple drug targets. Here, we established an expression system and purification procedures for full-length L protein, which is composed of an endonuclease domain, RdRp domain, and cap-binding domain. A cryo-EM L protein structure was reported at 3.6 Å resolution. In this first L protein structure of genus Phlebovirus, the priming loop of RVFV L protein is distinctly different from those of other L proteins and undergoes large movements related to its replication role. Structural and biochemical analyses indicate that a single template can induce initiation of RNA synthesis, which is notably enhanced by 5′ viral RNA. These findings help advance our understanding of the mechanism of RNA synthesis and provide an important basis for developing antiviral inhibitors. IMPORTANCE The zoonosis RVF virus (RVFV) is one of the most serious arbovirus threats to both human and animal health. RNA-dependent RNA polymerase (RdRp) is a multifunctional enzyme catalyzing genome replication as well as viral transcription, so the RdRp is essential for studying the virus and has multiple drug targets. In our study, we report the structure of RVFV L protein at 3.6 Å resolution by cryo-EM. This is the first L protein structure of genus Phlebovirus. Strikingly, a single template can initiate RNA replication. The structure and assays provide a comprehensive and in-depth understanding of the catalytic and substrate recognition mechanism of RdRp.
- Published
- 2022