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Published on: August 21, 2018
Engineering thermal stability in RNA phage capsids via disulphide bonds
Alison E Ashcroft1, Hugo Lago, Jacyara M B Macedo
1Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
Journal of Nanoscience and Nanotechnology
|January 25, 2006
Summary
Disulfide bonds in RNA bacteriophage Qbeta capsids enhance thermal stability compared to MS2. Engineering these bonds into MS2 at specific sites reveals insights into capsid assembly and redesign potential for bionanotechnology.
Area of Science:
- Biochemistry
- Structural Biology
- Nanotechnology
Background:
- RNA bacteriophages like Qbeta and MS2 have bionanotechnological applications.
- Qbeta and MS2 capsids exhibit different thermal stabilities despite similar protein structures.
- Qbeta's enhanced stability is attributed to inter-subunit disulfide bonds absent in MS2.
Purpose of the Study:
- To investigate the role of inter-subunit disulfide bonds in the thermal stability of RNA bacteriophage capsids.
- To test the hypothesis that disulfide bonds at specific capsid axes contribute to Qbeta's stability.
- To explore the potential for redesigning phage shell properties for bionanotechnology.
Main Methods:
- Mass spectrometry was used to analyze dissociated coat protein subunits.
- Engineered disulfide cross-links at five-fold and three-fold axes of recombinant MS2 capsid.
- Comparative analysis of thermal stability between wild-type and engineered MS2 capsids.
Main Results:
- Mass spectrometry suggested disulfide bonds form at the five-fold but not three-fold axes in Qbeta.
- Engineering five-fold disulfide cross-links in MS2 mimicked Qbeta's enhanced stability.
- Three-fold cross-linking prevented assembly of T=3 shells, indicating their role in assembly pathway.
Conclusions:
- Inter-subunit disulfide bonds, particularly at the five-fold axis, significantly enhance phage capsid thermal stability.
- The location of disulfide bonds influences capsid assembly, with five-fold structures being crucial.
- These findings demonstrate the feasibility of engineering phage shells for tailored physical properties and applications.
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