title: The molecular structure of adrenal medulla kinesin.
abstract: The molecular structure of bovine adrenal kinesin was studied by electron microscopy using the low-angle rotary shadowing technique. Adrenal kinesin exhibited either a folded or an extended configuration; the ratio of the two is dependent on the salt concentration. Almost all adrenal kinesin molecules were folded in a low-ionic solution, and the ratio of extended molecules increased to 40-50% in a solution containing 1 M ammonium acetate. Kinesin in the extended configuration displayed a rod-shaped structure with a mean length of about 80 nm. The morphologies of the ends were different; one end was composed of two globular particles, similar to the two-headed structure of myosin, while the other end had a more ill-defined structure, appearing either as a globular particle, an aggregate of two to four small granules, or a frayed, fan-like structure. The folded kinesin molecule possessed a hinge region in the middle of the rod, at about 32 nm from the neck of the two heads. In our preparations, the majority of adrenal kinesin molecules were folded at physiological salt concentrations. Adrenal kinesin bound to microtubules in the presence of adenylyl imidodiphosphate (AMP-PNP) also displayed a folded morphology.
authors.affiliation: Department of Anatomy and Cell Biology, Faculty of Medicine, University of Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Hisanaga
authors.forename: H
authors.initials: H
authors.lastname: Murofushi
authors.forename: K
authors.initials: K
authors.lastname: Okuhara
authors.forename: R
authors.initials: R
authors.lastname: Sato
authors.forename: Y
authors.initials: Y
authors.lastname: Masuda
authors.forename: H
authors.initials: H
authors.lastname: Sakai
authors.forename: N
authors.initials: N
authors.lastname: Hirokawa
mesh_terms: D000085:Acetates / Q000494:pharmacology; D000313:Adrenal Medulla / Q000032:analysis*; D000818:Animals; D002417:Cattle; D004591:Electrophoresis, Polyacrylamide Gel; D016547:Kinesins; D008854:Microscopy, Electron; D008870:Microtubules / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000648:ultrastructure*; D011487:Protein Conformation; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D000085:Acetates; D009419:Nerve Tissue Proteins; D012965:Sodium Chloride; D016547:Kinesins; C018824:ammonium acetate