title: Experimental free energy surface reconstruction from single-molecule force spectroscopy using Jarzynski's equality.
abstract: We used the atomic force microscope to manipulate and unfold individual molecules of the titin I27 domain and reconstructed its free energy surface using Jarzynski's equality. The free energy surface for both stretching and unfolding was reconstructed using an exact formula that relates the nonequilibrium work fluctuations to the molecular free energy. In addition, the unfolding free energy barrier, i.e., the activation energy, was directly obtained from experimental data for the first time. This Letter demonstrates that Jarzynski's equality can be used to analyze nonequilibrium single-molecule experiments, and to obtain the free energy surfaces for molecular systems, including interactions for which only nonequilibrium work can be measured.
authors.affiliation: Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA.
authors.forename: Nolan C
authors.initials: NC
authors.lastname: Harris
authors.forename: Yang
authors.initials: Y
authors.lastname: Song
authors.forename: Ching-Hwa
authors.initials: CH
authors.lastname: Kiang
mesh_terms: D003198:Computer Simulation; D064211:Connectin; D004735:Energy Transfer; D019277:Entropy; D006321:Heart / Q000502:physiology; D006801:Humans; D019563:Mechanics; D008565:Membrane Proteins / Q000737:chemistry; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D009124:Muscle Proteins / Q000737:chemistry*; D009132:Muscles / Q000378:metabolism; D017510:Protein Folding; D011494:Protein Kinases / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D064211:Connectin; D008565:Membrane Proteins; D009124:Muscle Proteins; C577285:TTN protein, human; D011494:Protein Kinases