title: Extending a spectrin repeat unit. I: linear force-extension response.
abstract: 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.
authors.affiliation: Center for Biophysical Modeling and Simulation and Department of Chemistry, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Sterling
authors.initials: S
authors.lastname: Paramore
authors.forename: Gary S
authors.initials: GS
authors.lastname: Ayton
authors.forename: Dina T
authors.initials: DT
authors.lastname: Mirijanian
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Voth
mesh_terms: D000465:Algorithms; D000818:Animals; D001703:Biophysics / Q000379:methods*; D001921:Brain / Q000378:metabolism; D002244:Carbon / Q000737:chemistry; D002645:Chickens; D003198:Computer Simulation; D003599:Cytoskeleton / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D018625:Microscopy, Atomic Force / Q000379:methods; D008954:Models, Biological; D015233:Models, Statistical; D008968:Molecular Conformation; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012984:Software; D013049:Spectrin / Q000737:chemistry* / Q000378:metabolism; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D013049:Spectrin; D002244:Carbon