Engineered mutations change the structure and stability of a virus-like particle

Biomacromolecules. 2012 Aug 13;13(8):2339-48. doi: 10.1021/bm300590x. Epub 2012 Jul 25.


The single-coat protein (CP) of bacteriophage Qβ self-assembles into T = 3 icosahedral virus-like particles (VLPs), of interest for a wide range of applications. These VLPs are very stable, but identification of the specific molecular determinants of this stability is lacking. To investigate these determinants along with manipulations that confer more capabilities to our VLP material, we manipulated the CP primary structure to test the importance of various putative stabilizing interactions. Optimization of a procedure to incorporate fused CP subunits allowed for good control over the average number of covalent dimers in each VLP. We confirmed that the disulfide linkages are the most important stabilizing elements for the capsid and that acidic conditions significantly enhance the resistance of VLPs to thermal degradation. Interdimer interactions were found to be less important for VLP assembly than intradimer interactions. Finally, a single point mutation in the CP resulted in a population of smaller VLPs in three distinct structural forms.

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

  • Allolevivirus / genetics*
  • Amino Acid Motifs
  • Amino Acid Substitution*
  • Capsid / chemistry
  • Capsid / ultrastructure
  • Capsid Proteins / biosynthesis
  • Capsid Proteins / chemistry
  • Capsid Proteins / genetics*
  • Escherichia coli
  • Hydrogen Bonding
  • Hydrophobic and Hydrophilic Interactions
  • Inverted Repeat Sequences
  • Light
  • Models, Molecular
  • Point Mutation
  • Protein Engineering
  • Protein Interaction Domains and Motifs
  • Protein Multimerization
  • Protein Stability
  • Protein Structure, Quaternary
  • Protein Unfolding
  • RNA, Viral / chemistry
  • RNA, Viral / genetics
  • Scattering, Radiation


  • Capsid Proteins
  • RNA, Viral