title: Nucleocapsid assembly in pneumoviruses is regulated by conformational switching of the N protein.
abstract: Non-segmented, (-)RNA viruses cause serious human diseases. Human metapneumovirus (HMPV), an emerging pathogen of this order of viruses (Mononegavirales) is one of the main causes of respiratory tract illness in children. To help elucidate the assembly mechanism of the nucleocapsid (the viral RNA genome packaged by the nucleoprotein N) we present crystallographic structures of HMPV N in its assembled RNA-bound state and in a monomeric state, bound to the polymerase cofactor P. Our structures reveal molecular details of how P inhibits the self-assembly of N and how N transitions between the RNA-free and RNA-bound conformational state. Notably, we observe a role for the C-terminal extension of N in directly preventing premature uptake of RNA by folding into the RNA-binding cleft. Our structures suggest a common mechanism of how the growth of the nucleocapsid is orchestrated, and highlight an interaction site representing an important target for antivirals.
authors.affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.
authors.forename: Max
authors.initials: M
authors.lastname: Renner
authors.affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.
authors.forename: Mattia
authors.initials: M
authors.lastname: Bertinelli
authors.affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.
authors.forename: Cédric
authors.initials: C
authors.lastname: Leyrat
authors.affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.
authors.forename: Guido C
authors.initials: GC
authors.lastname: Paesen
authors.affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.
authors.forename: Laura Freitas
authors.initials: LF
authors.lastname: Saraiva de Oliveira
authors.affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.
authors.forename: Juha T
authors.initials: JT
authors.lastname: Huiskonen
authors.affiliation: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.|Diamond Light Source, Didcot, United Kingdom.
authors.forename: Jonathan M
authors.identifier: http://orcid.org/0000-0001-9698-0389
authors.initials: JM
authors.lastname: Grimes
mesh_terms: D000494:Allosteric Regulation; D018360:Crystallography, X-Ray; D029121:Metapneumovirus / Q000502:physiology*; D008958:Models, Molecular; D019251:Nucleocapsid / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D012367:RNA, Viral / Q000378:metabolism; D015678:Viral Structural Proteins / Q000737:chemistry* / Q000378:metabolism*; D019065:Virus Assembly
chemical_list: D012367:RNA, Viral; D015678:Viral Structural Proteins
keywords: biophysics; infectious disease; microbiology; mononegavirales; nucleoprotein; pneumoviruses; structural biology; structural virology; virus; virus replication