Atomic model of CPV reveals the mechanism used by this single-shelled virus to economically carry out functions conserved in multishelled reoviruses

Structure. 2011 May 11;19(5):652-61. doi: 10.1016/j.str.2011.03.003.

Abstract

Unlike the multishelled viruses in the Reoviridae, cytoplasmic polyhedrosis virus (CPV) is single shelled, yet stable and fully capable of carrying out functions conserved within Reoviridae. Here, we report a 3.1 Å resolution cryo electron microscopy structure of CPV and derive its atomic model, consisting of 60 turret proteins (TPs), 120 each of capsid shell proteins (CSPs) and large protrusion proteins (LPPs). Two unique segments of CSP contribute to CPV's stability: an inserted protrusion domain interacting with neighboring proteins, and an N-anchor tying up CSPs together through strong interactions such as β sheet augmentation. Without the need to interact with outer shell proteins, LPP retains only the N-terminal two-third region containing a conserved helix-barrel core and interacts exclusively with CSP. TP is also simplified, containing only domains involved in RNA capping. Our results illustrate how CPV proteins have evolved in a coordinative manner to economically carry out their conserved functions.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Sequence
  • Capsid / chemistry*
  • Capsid / metabolism
  • Capsid Proteins / chemistry*
  • Capsid Proteins / metabolism
  • Cryoelectron Microscopy
  • Evolution, Molecular
  • Image Processing, Computer-Assisted
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation
  • Protein Stability
  • RNA, Viral / metabolism*
  • Reoviridae Infections / virology
  • Reoviridae* / chemistry
  • Reoviridae* / metabolism

Substances

  • Capsid Proteins
  • RNA, Viral

Associated data

  • PDB/3IZX