Crimean-Congo hemorrhagic fever virus nucleocapsid protein (CCHFV N (or N protein))

The **Crimean-Congo hemorrhagic fever virus nucleocapsid protein** (CCHFV N, also called nucleoprotein) is the principal protein responsible for encapsidating the viral genomic and antigenomic RNAs of CCHFV, a pathogenic tick-borne nairovirus in the Bunyaviridae family. The nucleocapsid protein is the most abundant structural protein in the virion and forms ribonucleoprotein complexes that are essential as templates for the virus-encoded RNA-dependent RNA polymerase during replication and transcription. CCHFV N binds viral RNA in both double-stranded and single-stranded conformations, facilitating both packaging and selective recognition of viral genome termini. Structurally, the protein exhibits flexible domains that allow for conformational changes upon RNA binding or oligomerization, and possesses a caspase-3 cleavage site likely involved in host defense and regulation of viral replication. Crystal structures reveal a domain architecture with a globular RNA-binding domain and an extended stalk or arm domain; it also displays distant homology with arenavirus N proteins. Single residue mutations affecting its unique endonuclease site significantly reduce this function, pointing to its importance in viral life cycle and as a therapeutic target. There are no current antiviral drugs targeting this protein in clinical use, but its essential roles in CCHFV replication underscore its attractiveness in antiviral development efforts.

Other names

nucleoprotein (NP)N proteinCCHFV nucleocapsid protein

For small molecules or biologics in preclinical stages (not clinically approved): thought to inhibit RNA binding or protein oligomerization, thus blocking virus replication