Electron Cryo-microscopy Structure of Ebola Virus Nucleoprotein Reveals a Mechanism for Nucleocapsid-like Assembly

Cell. 2018 Feb 22;172(5):966-978.e12. doi: 10.1016/j.cell.2018.02.009.


Ebola virus nucleoprotein (eNP) assembles into higher-ordered structures that form the viral nucleocapsid (NC) and serve as the scaffold for viral RNA synthesis. However, molecular insights into the NC assembly process are lacking. Using a hybrid approach, we characterized the NC-like assembly of eNP, identified novel regulatory elements, and described how these elements impact function. We generated a three-dimensional structure of the eNP NC-like assembly at 5.8 Å using electron cryo-microscopy and identified a new regulatory role for eNP helices α22-α23. Biochemical, biophysical, and mutational analyses revealed that inter-eNP contacts within α22-α23 are critical for viral NC assembly and regulate viral RNA synthesis. These observations suggest that the N terminus and α22-α23 of eNP function as context-dependent regulatory modules (CDRMs). Our current study provides a framework for a structural mechanism for NC-like assembly and a new therapeutic target.

Keywords: Ebola virus; cryo-EM; nucleocapsid; nucleoprotein; viral RNA synthesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Cryoelectron Microscopy*
  • Ebolavirus / physiology*
  • Ebolavirus / ultrastructure*
  • Models, Biological
  • Mutant Proteins / chemistry
  • Mutation / genetics
  • Nucleocapsid / ultrastructure*
  • Nucleoproteins / chemistry
  • Nucleoproteins / ultrastructure*
  • Protein Multimerization
  • Protein Structure, Secondary
  • Protein Subunits / chemistry
  • Protein Subunits / metabolism
  • RNA, Viral / biosynthesis
  • RNA, Viral / chemistry
  • RNA, Viral / metabolism
  • Virus Assembly*


  • Mutant Proteins
  • Nucleoproteins
  • Protein Subunits
  • RNA, Viral