The substructure of the components of the axoneme interior--the inner dynein arms, the radial spokes, and the central pair/projection complex--was analyzed for Chlamydomonas. Tetrahymena, Strongelocentrotus, and Mnemiopsis using the quick-freeze, deep-etch technique. The inner arms are shown to resemble the outer arms in overall molecular organization, but they are disposed differently on the microtubule and have two distinct morphologies--dyads with two heads and triads with three. The dyads associate with spokes S3 and S2; the triads associate with S1. The spokes form a three-start right-handed helix with a 288-nm rise; the central pair makes a shallow left-handed twist. The spoke heads are shown to be made up of four major subunits; two bind to the spoke shaft and two bind to a pair of central-sheath projections.
Substructure of inner dynein arms, radial spokes, and the central pair/projection complex of cilia and flagella.
U W Goodenough, J E Heuser; Substructure of inner dynein arms, radial spokes, and the central pair/projection complex of cilia and flagella.. J Cell Biol 1 June 1985; 100 (6): 2008–2018. doi: https://doi.org/10.1083/jcb.100.6.2008
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