8ASB

Structure of the SFTSV L protein stalled at early elongation with the endonuclease domain in a raised conformation [EARLY-ELONGATION-ENDO]

Summary for 8ASB

• Entry DOI: 10.2210/pdb8asb/pdb
• Related: 8AS6 8AS7 8ASB 8ASD
• EMDB information: 15610
• Descriptor: RNA-dependent RNA-polymerase L protein, RNA (5'-R(*AP*CP*AP*CP*AP*GP*AP*GP*AP*CP*GP*CP*CP*CP*AP*GP*A)-3'), RNA (5'-R(P*UP*CP*UP*GP*GP*GP*CP*GP*GP*UP*CP*UP*UP*UP*GP*UP*GP*U)-3'), ... (6 entities in total)
• Functional Keywords: sftsv rna-dependent rna polymerase, viral rna, viral protein
• Biological source: SFTS virus AH12; More
• Total number of polymer chains: 4
• Total formula weight: 259252.86

Authors

Williams, H.M.,Thorkelsson, S.R.,Vogel, D.,Milewski, M.,Busch, C.,Cusack, S.,Grunewald, K.,Quemin, E.R.J.,Rosenthal, M. (deposition date: 2022-08-18, release date: 2023-01-18, Last modification date: 2025-07-02)

Primary citation

Williams, H.M.,Thorkelsson, S.R.,Vogel, D.,Milewski, M.,Busch, C.,Cusack, S.,Grunewald, K.,Quemin, E.R.J.,Rosenthal, M.
Structural insights into viral genome replication by the severe fever with thrombocytopenia syndrome virus L protein.
Nucleic Acids Res., 51:1424-1442, 2023

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.

PubMed: 36651274
DOI: 10.1093/nar/gkac1249

Experimental method

ELECTRON MICROSCOPY (3.6 Å)