title: Thermodynamics of force-dependent folding and unfolding of small protein and nucleic acid structures.
abstract: In this paper, we outline the theoretical framework for understanding the equilibrium force-dependent folding and unfolding transitions of protein domains and small nucleic acid structures, both having small rigid folded structures and highly flexible unfolded polymeric chain conformations. A complete statistical description of the state described by the probability function ρ(ξ)(n,x), is obtained, where n is an index denoting the structural state, and x is the extension of the molecule. ξ denotes an external constraint applied to the molecule, which is either a constant force or a harmonic spring attached to one end of the molecule. The extension probability distribution regardless of the structural state: , the free energy landscape: -kBT ln(ρ(ξ)(x)), and the probability of the states regardless of the extension: , are analyzed using the force-dependent structural transitions of the classic titin I27 domain as an example. The impact of different external constraints is also discussed.
authors: Mechanobiology Institute, National University of Singapore, Singapore 117411. phyyj@nus.edu.sg.
authors: Mingxi
authors: M
authors: Yao
authors: Hu
authors: H
authors: Chen
authors: Jie
authors: J
authors: Yan
mesh_terms: D001696:Biomechanical Phenomena; D064211:Connectin / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009696:Nucleic Acids / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D058767:Protein Unfolding; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D064211:Connectin; D009696:Nucleic Acids; D011506:Proteins