Download MendeleyStructural insights into viral genome replication by the severe fever with thrombocytopenia syndrome virus L protein.
Williams, H.M., Thorkelsson, S.R., Vogel, D., Milewski, M., Busch, C., Cusack, S., Grunewald, K., Quemin, E.R.J., Rosenthal, M.(2023) Nucleic Acids Res 51: 1424-1442
- PubMed: 36651274
- DOI: https://doi.org/10.1093/nar/gkac1249
- Primary Citation of Related Structures:
8AS6, 8AS7, 8ASB, 8ASD, 8ASG - PubMed Abstract:
Severe fever with thrombocytopenia syndrome virus (SFTSV) is a phenuivirus that has rapidly become endemic in several East Asian countries. The large (L) protein of SFTSV, which includes the RNA-dependent RNA polymerase (RdRp), is responsible for catalysing viral genome replication and transcription. Here, we present 5 cryo-electron microscopy (cryo-EM) structures of the L protein in several states of the genome replication process, from pre-initiation to late-stage elongation, at a resolution of up to 2.6 Å. We identify how the L protein binds the 5' viral RNA in a hook-like conformation and show how the distal 5' and 3' RNA ends form a duplex positioning the 3' RNA terminus in the RdRp active site ready for initiation. We also observe the L protein stalled in the early and late stages of elongation with the RdRp core accommodating a 10-bp product-template duplex. This duplex ultimately splits with the template binding to a designated 3' secondary binding site. The structural data and observations are complemented by in vitro biochemical and cell-based mini-replicon assays. Altogether, our data provide novel key insights into the mechanism of viral genome replication by the SFTSV L protein and will aid drug development against segmented negative-strand RNA viruses.
Organizational Affiliation:
Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany.
