title: Structure of striated microtubule-associated fibers of flagellar roots. Comparison of native and reconstituted states.
abstract: Several fiber systems are associated with the flagella and basal bodies of eukaryotic cells. Apart from the contractile and Ca(2+)-sensitive system-II fibers, these include the noncontractile system-I fibers that run parallel to flagellar root microtubules. Using electron microscopy and image reconstruction, we have investigated the structure of the system-I fibers of the flagellate green alga Spermatozopsis similis. The fibers were observed in three different states: (1) in situ, (2) after isolation of the intact fibers, (3) after disassembly and reconstitution of fibers in vitro from their 34 kDa subunit protein. The fibers are highly ordered; they show a constant repeat of 28 nm, they are polar, and they contain several transverse and longitudinal striations. A model is discussed showing the system-I fiber to be built from rod-like molecules with a staggered arrangement and identical polarities.
authors.affiliation: Max-Planck-Unit for Structural Molecular Biology, DESY, Hamburg, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Patel
authors.forename: K F
authors.initials: KF
authors.lastname: Lechtreck
authors.forename: M
authors.initials: M
authors.lastname: Melkonian
authors.forename: E
authors.initials: E
authors.lastname: Mandelkow
mesh_terms: D000460:Chlorophyta / Q000737:chemistry / Q000648:ultrastructure*; D005407:Flagella / Q000737:chemistry / Q000648:ultrastructure*; D008854:Microscopy, Electron; D008870:Microtubules / Q000737:chemistry / Q000648:ultrastructure; D014961:X-Ray Diffraction