5e4v

Publication Abstract from PubMed

The enveloped negative-stranded RNA virus, measles virus (MeV) is an important human pathogen. The nucleoprotein (N0) assembles with the viral RNA into helical ribonucleocapsids (NC) which are in turn coated by a helical layer of the matrix protein. The viral polymerase complex uses the NC as its template. The N0 assembly onto the NC and the activity of the polymerase are regulated by the viral phosphoprotein (P). Here, we pulled down an N0 1-408 fragment lacking most of its C-terminal tail domain by several affinity-tagged, N-terminal, P fragments to map the N0-binding region of P to the first 48 amino acids. We showed biochemically and using P mutants the importance of the hydrophobic interactions for the binding. We fused an N0 binding peptide, P1-48, to the C-terminus of an N0 21-408 fragmentlacking both the N-terminal peptide and the C-terminal tail of N protein to reconstitute and crystallize the N0-P complex. We solved the X-ray structure of the resulting N0-P chimeric protein at 2.7 A resolution. The structure reveals the molecular details of the conserved N0-P interface and explains how P chaperones N0 preventing both self-assembly of N0 and its binding to RNA. Finally, we propose a model for a pre-initiation complex for RNA polymerization. IMPORTANCE: Measles virus is an important, highly contagious, human pathogen. The nucleoprotein N binds only to viral genomic RNA and forms the helical ribonucleocapsid that serves as a template for viral replication. We address how N is regulated by another protein, the phosphoprotein, P, to prevent newly synthesized N from binding to cellular RNA. We describe the atomic model of an N-P complex and compare it to helical ribonucleocapsid. We thus provide insight into how P chaperones N and helps to start viral RNA synthesis. Our results provide a new insight into mechanisms of paramyxovirus replication. New data on the mechanisms of phosphoprotein chaperone action allows better understanding of the virus genome replication and nucleocapsid assembly. We describe a conserved structural interface for the N-P interaction which could be a target for drug development not only to treat measles but also potentially other paramyxovirus diseases.

Crystal Structure of the Measles Virus Nucleoprotein Core in complex with an N-terminal Region of Phosphoprotein.,Guryanov SG, Liljeroos L, Kasaragod P, Kajander T, Butcher SJ J Virol. 2015 Dec 30. pii: JVI.02865-15. PMID:26719278^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.