title: Structure and assembly of the RNA binding domain of bluetongue virus non-structural protein 2.
abstract: Bluetongue virus non-structural protein 2 belongs to a class of highly conserved proteins found in orbiviruses of the Reoviridae family. Non-structural protein 2 forms large multimeric complexes and localizes to cytoplasmic inclusions in infected cells. It is able to bind single-stranded RNA non-specifically, and it has been suggested that the protein is involved in the selection and condensation of the Bluetongue virus RNA segments prior to genome encapsidation. We have determined the x-ray structure of the N-terminal domain (sufficient for the RNA binding ability of non-structural protein 2) to 2.4 A resolution using anomalous scattering methods. Crystals of this apparently insoluble domain were obtained by in situ proteolysis of a soluble construct. The asymmetric unit shows two monomers related by non-crystallographic symmetry, with each monomer folded as a beta sandwich with a unique topology. The crystal structure reveals extensive monomer-monomer interactions, which explain the ability of the protein to self-assemble into large homomultimeric complexes. Of the entire surface area of the monomer, one-third is used to create the interfaces of the curved multimeric assembly observed in the x-ray structure. The structure reported here shows how the N-terminal domain would be able to bind single-stranded RNA non-specifically protecting the bound regions in a heterogeneous multimeric but not polymeric complex.
authors.affiliation: European Molecular Biology Laboratory, c/o Deutsches Elektronen-Synchrotron, Notkestrasse 85, D-22603 Hamburg, Germany.
authors.forename: Carmen
authors.initials: C
authors.lastname: Butan
authors.forename: Hans
authors.initials: H
authors.lastname: Van Der Zandt
authors.forename: Paul A
authors.initials: PA
authors.lastname: Tucker
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D001820:Bluetongue virus / Q000378:metabolism*; D017931:DNA Primers; D008958:Models, Molecular; D008969:Molecular Sequence Data; D012367:RNA, Viral / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins