Issue Date: February 21, 2011
Dynein’s Motor Revealed
Nearly 50 years after the discovery of the walking molecular motor dynein, researchers have finally solved the first X-ray crystal structure of its massive motor domain. The milestone will permit researchers to tweak and tune the molecular engine that drives the transport of neurotransmitter vesicles, mRNA, and nuclei around biological cells and powers the beating of flagella and cilia.
Seven years after he first took a stab at solving dynein’s crystal structure as a postdoc, Andrew P. Carter, now a structural biologist at the Medical Research Council, in Cambridge, England., and Carol Cho, a graduate student in Ronald D. Vale’s cell biology lab at the University of California, San Francisco, finally elucidated the protein motor at 6-Å resolution (Science, DOI: 10.1126/science.1202393).
“This is a major breakthrough,” comments Stan Burgess, a biologist at Leeds University, in England, who publishes electron microscopy images of molecular motors. “Even though it is still not yet atomic resolution, the structure will transform the field of dynein research because it means we can now insert chemical cross-links and do mutagenesis to really see how [the motor] works.” The exact details of how dynein works have been just “arm waving” up until now, Burgess adds.
Dynein has been the most elusive to crystallize of the three molecular motors known to walk around cells on protein tracks. Structures of the other motors, myosin and kinesin, were more easily solved, likely because their motors are one-tenth of the size of dynein’s.
To get the X-ray crystal structure of dynein’s motor, the team had to remove the feet at the end of dynein’s lollipop-like structure, which walk along the protein track. They also had to remove dynein’s cargo domain, whose shape selects for the right freight.
Carter says he will now try to get a higher resolution picture of the motor domain to help figure out how the binding of adenosine triphosphate into four pockets in the motor powers the large conformational changes that permit dynein to step forward.
- Chemical & Engineering News
- ISSN 0009-2347
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