Measles virus nucleoprotein (N)

The measles virus nucleoprotein (N) is a structural viral protein that encapsidates the single-stranded negative-sense RNA genome at a ratio of 1 N per 6 ribonucleotides, forming a helical ribonucleocapsid (NC) that protects the genome from nucleases and serves as the template for viral RNA transcription and replication.[1][5][7][11] N consists of an ordered N_CORE domain (residues 1-391 or ~400), comprising N-terminal (NTD) and C-terminal (CTD) domains with flanking N- and C-terminal arms, and an intrinsically disordered N_TAIL domain (residues ~392-525) that anchors the polymerase complex.[1][5][9] The phosphoprotein (P) chaperones RNA-free N^0 to prevent non-specific cellular RNA binding, facilitating transfer to nascent NC during replication; structural studies show P's N-terminal region binding N_CORE to regulate this.[1][2][3][10] N assembles into helical NC following the "rule of six" nucleotides per protomer, with specific RNA-binding grooves and inter-protomer arm interactions stabilizing the structure.[6][9][11] N and P form liquid-like phase-separated droplets that accelerate nucleocapsid assembly.[3]

Other names

NucleoproteinN proteinN^0 (RNA-free form)