title: Significance of kinetic degrees of freedom in operation of the actomyosin motor.
abstract: The actomyosin motor as a principal functional component of cell motility is highly coordinated in regulating the participating molecular components. At the same time, it has to be flexible and plastic enough to accommodate itself to a wide variety of operational conditions. We prepared two different types of actomyosin systems. One is a natural intact actomyosin system with no artificial constraint on the kinetic degrees of freedom of the actin filaments, and the other is a regulated one with actin filaments supplemented by intra- and intermolecular crosslinking to suppress the kinetic degrees of freedom to a certain extent. Crosslinked actomyosin systems were found to remain almost insensitive to calcium regulation even when intact troponin-tropomyosin regulatory component was incorporated. Both the ATPase and the motile activities of the actin filaments sliding on myosin molecules were markedly lowered by the crosslinking. In contrast, once the crosslinking was cleaved, both properties returned to the normal as with intact actomyosin systems.
authors.affiliation: Department of BioEngineering, Nagaoka University of Technology, Nagaoka 940-2188, Japan. hatori@vos.nagaokaut.ac.jp
authors.forename: Kuniyuki
authors.initials: K
authors.lastname: Hatori
authors.forename: Takumi
authors.initials: T
authors.lastname: Tamura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kawano
authors.forename: Mari
authors.initials: M
authors.lastname: Tamura
authors.forename: Hajime
authors.initials: H
authors.lastname: Honda
mesh_terms: D000205:Actomyosin / Q000737:chemistry*; D000818:Animals; D002118:Calcium / Q000737:chemistry; D002465:Cell Movement; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D011817:Rabbits
chemical_list: D000205:Actomyosin; D002118:Calcium