Mechanical Properties of Inner-Arm Dynein-F (Dynein I1) Studied With In Vitro Motility Assays
| Autor: | Norito Kotani, Kazuhiro Oiwa, Stan A. Burgess, Hitoshi Sakakibara, Hiroaki Kojima |
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| Rok vydání: | 2007 |
| Předmět: |
Models
Molecular Axoneme biology Chlamydomonas Dynein Biophysics Dyneins macromolecular substances Processivity Flagellum Microtubule sliding biology.organism_classification Peptide Fragments Cell biology Microscopy Electron Bacterial Proteins Cell Movement Flagella Microtubule Dynactin Animals Muscle and Contractility Ca(2+) Mg(2+)-ATPase Chlamydomonas reinhardtii |
| Zdroj: | Biophysical Journal. 93:886-894 |
| ISSN: | 0006-3495 |
| DOI: | 10.1529/biophysj.106.101964 |
| Popis: | Inner-arm dynein-f of Chlamydomonas flagella is a heterodimeric dynein. We performed conventional in vitro motility assays showing that dynein-f translocates microtubules at the comparatively low velocity of approximately 1.2 microm/s. From the dependence of velocity upon the surface density of dynein-f, we estimate its duty ratio to be 0.6-0.7. The relation between microtubule landing rate and surface density of dynein-f are well fitted by the first-power dependence, as expected for a processive motor. At low dynein densities, progressing microtubules rotate erratically about a fixed point on the surface, at which a single dynein-f molecule is presumably located. We conclude that dynein-f has high processivity. In an axoneme, however, slow and processive dynein-f could impede microtubule sliding driven by other fast dyneins (e.g., dynein-c). To obtain insight into the in vivo roles of dynein-f, we measured the sliding velocity of microtubules driven by a mixture of dyneins -c and -f at various mixing ratios. The velocity is modulated as a function of the ratio of dynein-f in the mixture. This modulation suggests that dynein-f acts as a load in the axoneme, but force pushing dynein-f molecules forward seems to accelerate their dissociation from microtubules. |
| Databáze: | OpenAIRE |
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