Abstract
The elasticity of α -helices is examined using equilibrium molecular-dynamics simulations. From the statistics of curvatures and twists, we compute the elastic moduli of several representative α -helices, both in the presence and absence of aqueous solvent. We discover that the bending modulus (persistence length) of the helices is independent of the amino-acid sequence, although helices in water are slightly softer than in vacuum. The response of the helices under the action of an external force is also computed and compared with continuum mechanics predictions. Within the time scale of our simulation, we show that the properties of α -helices are well reproduced by an elastic and isotropic rod. The persistence length (bending modulus) of most α -helices in water or vacuum is ≈100 nm, roughly twice that of DNA.
| Original language | English |
|---|---|
| Article number | 244912 |
| Journal | Journal of Chemical Physics |
| Volume | 122 |
| Issue number | 24 |
| DOIs | |
| State | Published - 2005 |
Bibliographical note
Funding Information:The authors would like to thank Robert Kazmerisky and Joseph Lee for contributing to the early stages of this work. The authors (S.C. and S.S.) are supported by the Whitaker Biomedical Engineering Leadership award.