Related Experiment Videos
Structural characterization of a dynein motor domain
M Samsó1, M Radermacher, J Frank
1Department of Biomedical Sciences, State University of New York, Albany 12201-0509, USA.
Journal of Molecular Biology
|May 5, 1998
Summary
Cytoplasmic dynein, a motor protein essential for cell functions, was visualized using electron microscopy. Researchers detailed its head domain structure, revealing a unique ring of globular lobes surrounding a central cavity.
Area of Science:
- Cell Biology
- Structural Biology
- Biochemistry
Background:
- Cytoplasmic dynein is a crucial microtubule-based motor protein.
- It is involved in vital cellular processes like cell division and transport.
- Understanding its structure is key to understanding its function.
Purpose of the Study:
- To visualize and characterize the structural features of the dynein head domain.
- To provide the first detailed structural description of the dynein head.
Main Methods:
- Transmission electron microscopy (TEM) of native dynein from Dictyostelium.
- Image processing using SPIDER software for 2D averaging.
- Analysis of a recombinant dynein heavy chain fragment.
- Low-resolution 3D reconstruction using single tilt pair images.
Main Results:
- 2D averages revealed an oblong shape with 7-8 globular lobes.
- A recombinant fragment showed high structural similarity to the native head and a prominent stalk.
- 3D reconstructions showed a flattened spheroidal shape (13.5 nm) with 7 domains in a ring.
- A large central cavity was identified within the dynein head structure.
Conclusions:
- This study provides the first detailed structural description of the dynein head domain.
- The dynein head features a central cavity and outer globular domains, distinguishing it from myosin and kinesin.
- The identified stalk structure is analogous to the B-link in axonemal dyneins.