title: Molecular motion and cardiac muscle motor dynamics.
abstract: This paper reports on the kinetics of molecular motion in cardiac (and skeletal) muscles, studied by image analysis of the motility assay of an isolated actin filament sliding over isolated myosin heads that perform as linear motors. Image analysis allows us to study the dynamics of the crossbridges (Xbs) formed by the interactions between the actin molecule and the myosin heads, and to explore the rate kinetics of the interactions between the two. A most significant result pertains to the identification and characterization of two kinds of kinetics involved in Xb dynamics. The analysis of the acquired images suggests that Xb dynamics is determined by two distinctive kinetic mechanisms: fast physical kinetics that relates to the actin-myosin Xb attachment and detachment cycle and a process that is orders of magnitude slower in biochemical kinetics that relates to the reactions of nucleotide binding and dissociation.
authors.affiliation: Department of Biomedical Engineering, Technion, Israel Institute of Technology, Haifa, Israel. amir@biomed.technion.ac.il
authors.forename: Amir
authors.initials: A
authors.lastname: Landesberg
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Landesberg
authors.forename: Samuel
authors.initials: S
authors.lastname: Sideman
authors.forename: Henk E D J
authors.initials: HE
authors.lastname: Ter Keurs
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D006321:Heart / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D007700:Kinetics; D020409:Molecular Motor Proteins / Q000502:physiology*; D009206:Myocardium / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism; D010210:Papillary Muscles / Q000502:physiology*; D012984:Software
chemical_list: D000199:Actins; D020409:Molecular Motor Proteins; D009218:Myosins