Published online by Cambridge University Press: 26 February 2011
Coiled-coil alpha-helical dimers are the elementary building blocks of intermediate filaments (IFs), an important component of the cell's cytoskeleton. Therefore, IFs play a leading role in the mechanical integrity of the cells. Here we use atomistic simulation to carry out tensile tests on coiled-coils as well as on single alpha-helices of the 2B segment of the vimentin dimer that has been shown to control the large-deformation behavior of cells. We compare the characteristic force-strain curves of both structures and suggest explanations for the differences on this fundamental level of hierarchical assembly. We further systematically explore the strain rate dependence of the mechanical properties of the vimentin coiled-coil protein. We develop a simple continuum model capable of reproducing the atomistic modeling results. The model enables us to extrapolate to much lower deformation rates approaching those used in experiment.