title: Decoration of the microtubule surface by one kinesin head per tubulin heterodimer.
abstract: Kinesin, a microtubule-dependent ATPase, is believed to be involved in anterograde axonal transport. The kinesin head, which contains both microtubule and ATP binding sites, has the necessary components for the generation of force and motility. We have used saturation binding and electron microscopy to examine the interaction of the kinesin motor domain with the microtubule surface and found that binding saturated at one kinesin head per tubulin heterodimer. Both negative staining and cryo-electron microscopy revealed a regular pattern of kinesin bound to the microtubule surface, with an axial repeat of 8 nm. Optical diffraction analysis of decorated microtubules showed a strong layer-line at this spacing, confirming that one kinesin head binds per tubulin heterodimer. The addition of Mg-ATP to the microtubule-kinesin complex resulted in the complete dissociation of kinesin from the microtubule surface.
authors.affiliation: Department of Molecular and Cell Biology, Pennsylvania State University, University Park, 16802.
authors.forename: B C
authors.initials: BC
authors.lastname: Harrison
authors.forename: S P
authors.initials: SP
authors.lastname: Marchese-Ragona
authors.forename: S P
authors.initials: SP
authors.lastname: Gilbert
authors.forename: N
authors.initials: N
authors.lastname: Cheng
authors.forename: A C
authors.initials: AC
authors.lastname: Steven
authors.forename: K A
authors.initials: KA
authors.lastname: Johnson
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D004330:Drosophila; D004591:Electrophoresis, Polyacrylamide Gel; D005615:Freezing; D016547:Kinesins / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D008970:Molecular Weight; D017239:Paclitaxel / Q000494:pharmacology; D011485:Protein Binding; D011994:Recombinant Proteins / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D014404:Tubulin / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D046911:Macromolecular Substances; D011994:Recombinant Proteins; D014404:Tubulin; D000255:Adenosine Triphosphate; D016547:Kinesins; D017239:Paclitaxel