title: Single molecule thermodynamics in biological motors.
abstract: Biological molecular machines use thermal activation energy to carry out various functions. The process of thermal activation has the stochastic nature of output events that can be described according to the laws of thermodynamics. Recently developed single molecule detection techniques have allowed each distinct enzymatic event of single biological machines to be characterized providing clues to the underlying thermodynamics. In this study, the thermodynamic properties in the stepping movement of a biological molecular motor have been examined. A single molecule detection technique was used to measure the stepping movements at various loads and temperatures and a range of thermodynamic parameters associated with the production of each forward and backward step including free energy, enthalpy, entropy and characteristic distance were obtained. The results show that an asymmetry in entropy is a primary factor that controls the direction in which the motor will step. The investigation on single molecule thermodynamics has the potential to reveal dynamic properties underlying the mechanisms of how biological molecular machines work.
authors.affiliation: Laboratories for Nanobiology, Graduate School of Frontier Biosciences, Osaka University, 1-3, Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Taniguchi
authors.forename: Peter
authors.initials: P
authors.lastname: Karagiannis
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Nishiyama
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ishii
authors.forename: Toshio
authors.initials: T
authors.lastname: Yanagida
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D066298:In Vitro Techniques; D016547:Kinesins / Q000737:chemistry / Q000502:physiology; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000502:physiology*; D009038:Motion; D013269:Stochastic Processes; D049490:Systems Biology; D013816:Thermodynamics
chemical_list: D020409:Molecular Motor Proteins; D016547:Kinesins