Dynein ATPases power diverse microtubule-based motilities. Each dynein motor domain comprises a ring-like head containing six AAA+ modules and N- and C-terminal regions, together with a stalk that binds microtubules. How these subdomains are arranged and generate force remains poorly understood. Here, using electron microscopy and image processing of tagged and truncated Dictyostelium cytoplasmic dynein constructs, we show that the heart of the motor is a hexameric ring of AAA+ modules, with the stalk emerging opposite the primary ATPase site (AAA1). The C-terminal region is not an integral part of the ring but spans between AAA6 and near the stalk base. The N-terminal region includes a lever-like linker whose N terminus swings by approximately 17 nm during the ATPase cycle between AAA2 and the stalk base. Together with evidence of stalk tilting, which may communicate changes in microtubule binding affinity, these findings suggest a model for dynein's structure and mechanism.
Pubmed ID: 19203583 RIS Download
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An image analysis software that can process spectra and other multi-dimensional data-sets. The software package is aimed at processing large data sets from (cryo-) electron microscopy, especially in the field of single particle analyses. This software can be used with light and raster-tunneling microscopes, computer tomographs, FT-IR spectrometers and other signal collecting devices. This resource provides three-dimensional data processing and angular reconstitution modules that allow the three-dimensional reconstruction with point-group symmetry from the two dimensional electron microscopy projections. These models aid in the analysis of the macromolecules.
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