Toscana virus nucleoprotein oligomer organization observed in solution

Acta Crystallogr D Struct Biol. 2017 Aug 1;73(Pt 8):650-659. doi: 10.1107/S2059798317008774. Epub 2017 Jul 28.


Toscana virus (TOSV) is an arthropod-borne virus belonging to the Phlebovirus genus within the Bunyaviridae family. As in other bunyaviruses, the genome of TOSV is made up of three RNA segments. They are encapsidated by the nucleoprotein (N), which also plays an essential role in virus replication. To date, crystallographic structures of phlebovirus N have systematically revealed closed-ring organizations which do not fully match the filamentous organization of the ribonucleoprotein (RNP) complex observed by electron microscopy. In order to further bridge the gap between crystallographic data on N and observations of the RNP by electron microscopy, the structural organization of recombinant TOSV N was investigated by an integrative approach combining X-ray diffraction crystallography, transmission electron microscopy, small-angle X-ray scattering, size-exclusion chromatography and multi-angle laser light scattering. It was found that in solution TOSV N forms open oligomers consistent with the encapsidation mechanism of phlebovirus RNA.

Keywords: SAXS; Toscana virus; negative-sense single-stranded RNA virus; negative-stain TEM; nucleoprotein oligomers; nucleoproteins; oligomers; phlebovirus; ribonucleoprotein.

MeSH terms

  • Bunyaviridae Infections / virology
  • Crystallography, X-Ray
  • Models, Molecular
  • Nucleocapsid Proteins / chemistry*
  • Nucleocapsid Proteins / metabolism
  • Nucleocapsid Proteins / ultrastructure
  • Nucleoproteins / chemistry*
  • Nucleoproteins / metabolism
  • Nucleoproteins / ultrastructure
  • Protein Conformation
  • Protein Multimerization
  • RNA, Viral / metabolism
  • Sandfly fever Naples virus / chemistry*
  • Sandfly fever Naples virus / metabolism
  • Scattering, Small Angle
  • Solutions
  • X-Ray Diffraction


  • Nucleocapsid Proteins
  • Nucleoproteins
  • RNA, Viral
  • Solutions