title: Submillisecond elastic recoil reveals molecular origins of fibrin fiber mechanics.
abstract: Fibrin fibers form the structural scaffold of blood clots. Thus, their mechanical properties are of central importance to understanding hemostasis and thrombotic disease. Recent studies have revealed that fibrin fibers are elastomeric despite their high degree of molecular ordering. These results have inspired a variety of molecular models for fibrin's elasticity, ranging from reversible protein unfolding to rubber-like elasticity. An important property that has not been explored is the timescale of elastic recoil, a parameter that is critical for fibrin's mechanical function and places a temporal constraint on molecular models of fiber elasticity. Using high-frame-rate imaging and atomic force microscopy-based nanomanipulation, we measured the recoil dynamics of individual fibrin fibers and found that the recoil was orders of magnitude faster than anticipated from models involving protein refolding. We also performed steered discrete molecular-dynamics simulations to investigate the molecular origins of the observed recoil. Our results point to the unstructured αC regions of the otherwise structured fibrin molecule as being responsible for the elastic recoil of the fibers.
authors.affiliation: Immune Disease Institute, Children's Hospital Boston, Massachusetts, USA.
authors.forename: Nathan E
authors.initials: NE
authors.lastname: Hudson
authors.forename: Feng
authors.initials: F
authors.lastname: Ding
authors.forename: Igal
authors.initials: I
authors.lastname: Bucay
authors.forename: E Timothy
authors.initials: ET
authors.lastname: O'Brien
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Gorkun
authors.forename: Richard
authors.initials: R
authors.lastname: Superfine
authors.forename: Susan T
authors.initials: ST
authors.lastname: Lord
authors.forename: Nikolay V
authors.initials: NV
authors.lastname: Dokholyan
authors.forename: Michael R
authors.initials: MR
authors.lastname: Falvo
mesh_terms: D000595:Amino Acid Sequence; D001696:Biomechanical Phenomena; D004548:Elasticity; D005337:Fibrin / Q000737:chemistry*; D006801:Humans; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D013997:Time Factors
chemical_list: D005337:Fibrin