Conformational Plasticity of Hepatitis C Virus Core Protein Enables RNA-Induced Formation of Nucleocapsid-like Particles

J Mol Biol. 2018 Aug 3;430(16):2453-2467. doi: 10.1016/j.jmb.2017.10.010. Epub 2017 Oct 16.

Abstract

Many of the unanswered questions associated with hepatitis C virus assembly are related to the core protein (HCVcp), which forms an oligomeric nucleocapsid encompassing the viral genome. The structural properties of HCVcp have been difficult to quantify, at least in part because it is an intrinsically disordered protein. We have used single-molecule Förster Resonance Energy Transfer techniques to study the conformational dimensions and dynamics of the HCVcp nucleocapsid domain (HCVncd) at various stages during the RNA-induced formation of nucleocapsid-like particles. Our results indicate that HCVncd is a typical intrinsically disordered protein. When it forms small ribonucleoprotein complexes with various RNA hairpins from the 3' end of the HCV genome, it compacts but remains intrinsically disordered and conformationally dynamic. Above a critical RNA concentration, these ribonucleoprotein complexes rapidly and cooperatively assemble into large nucleocapsid-like particles, wherein the individual HCVncd subunits become substantially more extended.

Keywords: FRET; hepatitis C virus; intrinsic disorder; nucleocapsid assembly; single-molecule.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Circular Dichroism
  • Fluorescence Resonance Energy Transfer
  • Hepacivirus / genetics*
  • Hepacivirus / physiology
  • Models, Molecular
  • Molecular Conformation
  • Nucleocapsid / metabolism
  • Protein Binding
  • RNA, Viral / metabolism*
  • Ribonucleoproteins / metabolism
  • Viral Core Proteins / chemistry*
  • Viral Core Proteins / metabolism*
  • Virus Assembly

Substances

  • RNA, Viral
  • Ribonucleoproteins
  • Viral Core Proteins
  • nucleocapsid protein, Hepatitis C virus