Download MendeleyCryo-EM structures of CCHFV polymerase reveal a stepwise initiation stabilization pathway and a dual-site inhibition mechanism.
Yang, K., Wu, H., Liu, X., Liang, Z., Zou, J., Wang, Y., Ma, J.(2026) Cell Rep 45: 117945-117945
- PubMed: 42696455 Search on PubMed
- DOI: https://doi.org/10.1016/j.celrep.2026.117945
- Primary Citation Related Structures:
22TE, 22TH, 22TR, 26JZ, 26KA, 26KB, 26KD - PubMed Abstract:
Crimean-Congo hemorrhagic fever virus (CCHFV) is a high-priority pathogen with high case-fatality rates, yet approved therapeutics remain unavailable. The CCHFV L segment encodes a ∼450-kDa RNA-dependent RNA polymerase (L protein) orchestrating viral replication, but its structural mechanisms remain elusive. Here, we present high-resolution cryo-EM structures of the CCHFV L protein in apo, 5' vRNA-bound, 5'/3' promoter-bound, and inhibitor-bound states. The catalytic core exhibits the canonical architecture of the Bunyavirales order, featuring conserved motifs and coordinated promoter recognition via a 5' vRNA "hook" and a secondary 3' vRNA-binding site. Using suramin as a probe, we identified a dual-site mechanism of polymerase inhibition. Suramin competitively occludes the 5' vRNA-binding pocket through electrostatic mimicry of the RNA backbone and concurrently traps a distal linker-fingers interface, restricting the conformational dynamics required for catalysis. Collectively, these findings provide structural insights into CCHFV polymerase regulation and inhibition.
- Institute of Infectious Diseases, Shenzhen Bay Laboratory, Shenzhen, Guangdong 518132, China.
Organizational Affiliation:
