Structure and Dynamics of the Unassembled Nucleoprotein of Rabies Virus in Complex with Its Phosphoprotein Chaperone Module

• Published in: Viruses Vol. 14; no. 12; p. 2813
• Main Authors: Gérard, Francine C A, Bourhis, Jean-Marie, Mas, Caroline, Branchard, Anaïs, Vu, Duc Duy, Varhoshkova, Sylvia, Leyrat, Cédric, Jamin, Marc
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 16.12.2022; MDPI
• Subjects: Crystal structure; Genomes; Interfaces; Life Sciences; Molecular Chaperones; Molecular Chaperones - metabolism; Mononegavirales; N protein; nucleocapsid assembly; Nucleocapsid Proteins; Nucleocapsid Proteins - genetics; Nucleocapsids; Nucleoproteins; Nucleoproteins - metabolism; P protein; Peptides; phosphoprotein; Phosphoproteins; Phosphoproteins - genetics; Physiological aspects; Protein Binding; Proteins; Rabies; Rabies virus; Rabies virus - genetics; Rhabdoviruses; RNA; RNA - metabolism; RNA polymerase; RNA viruses; RNA, Viral; RNA, Viral - metabolism; small-angle X-ray scattering; Structure; Viral proteins; Viruses; X-ray crystallography; Zoonoses; France; X-ray crystallography; nucleocapsid assembly; rabies virus; Mononegavirales; phosphoprotein; molecular dynamics simulation; small-angle X-ray scattering
• ISSN: 1999-4915; 1999-4915
• DOI: 10.3390/v14122813

As for all non-segmented negative RNA viruses, rabies virus has its genome packaged in a linear assembly of nucleoprotein (N), named nucleocapsid. The formation of new nucleocapsids during virus replication in cells requires the production of soluble N protein in complex with its phosphoprotein (P) chaperone. In this study, we reconstituted a soluble heterodimeric complex between an armless N protein of rabies virus (RABV), lacking its N-terminal subdomain (N ), and a peptide encompassing the N chaperon module of the P protein. We showed that the chaperone module undergoes a disordered-order transition when it assembles with N and measured an affinity in the low nanomolar range using a competition assay. We solved the crystal structure of the complex at a resolution of 2.3 Å, unveiling the details of the conserved interfaces. MD simulations showed that both the chaperon module of P and RNA-mediated polymerization reduced the ability of the RNA binding cavity to open and close. Finally, by reconstituting a complex with full-length P protein, we demonstrated that each P dimer could independently chaperon two N molecules.