Molecular architecture of inner dynein arms in situ in Chlamydomonas reinhardtii flagella
The Journal of cell biology, 2008•rupress.org
The inner dynein arm regulates axonemal bending motion in eukaryotes. We used cryo-
electron tomography to reconstruct the three-dimensional structure of inner dynein arms
from Chlamydomonas reinhardtii. All the eight different heavy chains were identified in one
96-nm periodic repeat, as expected from previous biochemical studies. Based on mutants,
we identified the positions of the AAA rings and the N-terminal tails of all the eight heavy
chains. The dynein f dimer is located close to the surface of the A-microtubule, whereas the …
electron tomography to reconstruct the three-dimensional structure of inner dynein arms
from Chlamydomonas reinhardtii. All the eight different heavy chains were identified in one
96-nm periodic repeat, as expected from previous biochemical studies. Based on mutants,
we identified the positions of the AAA rings and the N-terminal tails of all the eight heavy
chains. The dynein f dimer is located close to the surface of the A-microtubule, whereas the …
The inner dynein arm regulates axonemal bending motion in eukaryotes. We used cryo-electron tomography to reconstruct the three-dimensional structure of inner dynein arms from Chlamydomonas reinhardtii. All the eight different heavy chains were identified in one 96-nm periodic repeat, as expected from previous biochemical studies. Based on mutants, we identified the positions of the AAA rings and the N-terminal tails of all the eight heavy chains. The dynein f dimer is located close to the surface of the A-microtubule, whereas the other six heavy chain rings are roughly colinear at a larger distance to form three dyads. Each dyad consists of two heavy chains and has a corresponding radial spoke or a similar feature. In each of the six heavy chains (dynein a, b, c, d, e, and g), the N-terminal tail extends from the distal side of the ring. To interact with the B-microtubule through stalks, the inner-arm dyneins must have either different handedness or, more probably, the opposite orientation of the AAA rings compared with the outer-arm dyneins.
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