Extending a Spectrin Repeat Unit. I: Linear Force-Extension Response

TitleExtending a Spectrin Repeat Unit. I: Linear Force-Extension Response
Publication TypeJournal Article
Year of Publication2006
AuthorsParamore, S, Ayton, GS, Mirijanian, DT, Voth, GA
JournalBiophys J
KeywordsAlgorithms Animals Biophysics/*methods Brain/metabolism Carbon/chemistry Chickens Computer Simulation Cytoskeleton/chemistry Magnetic Resonance Spectroscopy Microscopy, Atomic Force/methods Models, Biological Models, Secondary Software Spectrin/*chemistry/metabolism Thermodynamics Water/chemistry, Statistical Molecular Conformation Protein Conformation Protein Denaturation Protein Folding Protein Structure

Nonequilibrium molecular dynamics simulations were used to calculate the elastic properties of a spectrin repeat unit. A contiguous alpha-helical linker was constructed by employing periodic boundary conditions, allowing a novel scheme for evaluating the thermodynamic force as a function of extension. By measuring the force-extension response under small extensions, spectrin was observed to behave primarily as an elastic material with a spring constant of 1700 +/- 100 pN/nm. The implications of this spring constant, in terms of the properties of the spectrin tetramer, are also discussed.