title: High-speed force spectroscopy unfolds titin at the velocity of molecular dynamics simulations.
abstract: The mechanical unfolding of the muscle protein titin by atomic force microscopy was a landmark in our understanding of single-biomolecule mechanics. Molecular dynamics simulations offered atomic-level descriptions of the forced unfolding. However, experiment and simulation could not be directly compared because they differed in pulling velocity by orders of magnitude. We have developed high-speed force spectroscopy to unfold titin at velocities reached by simulation (~4 millimeters per second). We found that a small β-strand pair of an immunoglobulin domain dynamically unfolds and refolds, buffering pulling forces up to ~100 piconewtons. The distance to the unfolding transition barrier is larger than previously estimated but is in better agreement with atomistic predictions. The ability to directly compare experiment and simulation is likely to be important in studies of biomechanical processes.
authors.affiliation: U1006 INSERM, Aix-Marseille Université, Parc Scientifique et Technologique de Luminy, 163 avenue de Luminy, 13009 Marseille, France.
authors.forename: Felix
authors.initials: F
authors.lastname: Rico
authors.forename: Laura
authors.initials: L
authors.lastname: Gonzalez
authors.forename: Ignacio
authors.initials: I
authors.lastname: Casuso
authors.forename: Manel
authors.initials: M
authors.lastname: Puig-Vidal
authors.forename: Simon
authors.initials: S
authors.lastname: Scheuring
mesh_terms: D064211:Connectin / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D058767:Protein Unfolding; D013057:Spectrum Analysis / Q000379:methods*
chemical_list: D064211:Connectin