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Elasticity theory of macromolecular aggregates
A Aggarwal1, J Rudnick, R F Bruinsma
1Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, USA.
Physical Review Letters
|October 23, 2012
Summary
We developed a new elasticity theory for biomolecules, revealing how protein stresses drive shape changes in viruses like HK97. This explains viral shell transitions from icosahedral to dodecahedral forms.
Area of Science:
- Biophysics
- Structural Biology
- Computational Biology
Background:
- Classical elasticity theory does not account for molecular-level details in biomolecular aggregates.
- Functional biomolecules exhibit conformational changes that influence their mechanical properties.
Purpose of the Study:
- To adapt continuum elasticity theory for functional biomolecule aggregates at the molecular scale.
- To investigate the role of molecular incompatibilities in driving large-scale conformational transitions.
Main Methods:
- Developed a modified continuum elasticity theory incorporating discontinuities at macromolecular interfaces.
- Applied the theory to model the P-II to EI shape transition of the HK97 virus capsid.
- Analyzed the impact of protein residual stresses on capsid morphology.
Main Results:
- Demonstrated mathematical discontinuities in stress and strain fields due to conformational incompatibility.
- Showed that protein residual stresses induce a "reverse buckling" transition.
- Identified a critical spherical shape (P-II state) preceding the dodecahedral transformation.
Conclusions:
- The new elasticity theory accurately describes biomolecular mechanical behavior at the molecular scale.
- Protein residual stresses are key drivers of viral capsid shape transitions.
- The P-II state represents a critical intermediate in the HK97 capsid's structural remodeling.
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