title: The mode of ATP-dependent microtubule-kinesin sliding in the auxotonic condition.
abstract: Kinesin is a motor protein that converts chemical energy derived from ATP hydrolysis into mechanical work to transport cellular components along microtubules. We studied the properties of ATP-dependent microtubule-kinesin sliding with two different in vitro assay systems. In one assay system, a kinesin-coated glass microneedle (elastic coefficient, 1-2.5 pN microns -1) was made to slide along an axoneme. Using this system, we obtained the relationship between the force (= load) on the microneedle and the velocity of microneedle-kinesin sliding in the auxotonic condition, in which the load on the microtubule-kinesin contacts increased as sliding progressed. The force-velocity curve was upwardly convex (maximum velocity Vmax, 0.58 +/- 0.15 microns s-1; maximum isometric force P0, 5.0 +/- 1.6 pN) and was similar to that of in vitro actin-myosin sliding in the auxotonic condition, suggesting that the two motor protein systems have fundamental kinetic properties in common. In the other assay system, an axoneme attached to a glass microneedle (elastic coefficient, 4-5 pN microns -1) was made to slide on a kinesin-coated glass surface (Vmax, 0.68 +/- 0.17 microns s-1; P0, 46.1 +/- 18.6 pN). The change in shape of the axoneme indicated an enormous flexibility of randomly oriented kinesin molecules.
authors.affiliation: Department of Physiology, School of Medicine, Teikyo University, Tokyo, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Shirakawa
authors.forename: K
authors.initials: K
authors.lastname: Oiwa
authors.forename: S
authors.initials: S
authors.lastname: Chaen
authors.forename: T
authors.initials: T
authors.lastname: Shimizu
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Sugi
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002417:Cattle; D005898:Glass; D016547:Kinesins / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008870:Microtubules / Q000378:metabolism*; D009339:Needles; D012617:Sea Urchins; D013094:Spermatozoa / Q000648:ultrastructure
chemical_list: D000255:Adenosine Triphosphate; D016547:Kinesins