title: Tubulin bistability and polymorphic dynamics of microtubules.
abstract: Based on the hypothesis that the GDP-tubulin dimer is a conformationally bistable molecule-rapidly fluctuating between a discrete curved and a straight state-we develop a model for polymorphic dynamics of the microtubule lattice. We show that GDP-tubulin bistability consistently explains unusual dynamic fluctuations, the apparent length-stiffness relation of grafted taxol-stabilized microtubules, and the curved-helical appearance of microtubules in general. When clamped by one end the microtubules undergo an unusual zero energy motion-in its effect reminiscent of a limited rotational hinge. We conclude that microtubules exist in highly cooperative energy-degenerate helical states and discuss possible implications in vivo.
authors.affiliation: Groupe BioPhysStat, Université Paul Verlaine, Metz, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Mohrbach
authors.forename: Albert
authors.initials: A
authors.lastname: Johner
authors.forename: Igor M
authors.initials: IM
authors.lastname: Kulić
mesh_terms: D006153:Guanosine Diphosphate / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D008954:Models, Biological; D055550:Protein Stability; D014404:Tubulin / Q000378:metabolism*
chemical_list: D014404:Tubulin; D006153:Guanosine Diphosphate