Electron microscopy of Dictyostelium cytoplasmic dynein revealed a hexameric ring of AAA+ modules with a lever-like linker that swings approximately 17 nm during the ATPase cycle.
Elucidates the structural arrangement and swing mechanism of the dynein motor domain during the ATPase cycle.
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.
Roberts et al. (Sun,) conducted a other in Dynein motor structure. Electron microscopy of Dictyostelium cytoplasmic dynein constructs was evaluated on Structural arrangement and force generation mechanism. Electron microscopy of Dictyostelium cytoplasmic dynein revealed a hexameric ring of AAA+ modules with a lever-like linker that swings approximately 17 nm during the ATPase cycle.