Browsing by keyword "Trout"
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Outer arm dynein from trout spermatozoa. Purification, polypeptide composition, and enzymatic propertiesExtraction of isolated axonemes from trout (Salmo gairdneri) sperm with 0.6 M NaCl removed 97% of the outer arms, approximately 12% of the protein, and approximately 50% of the MgATPase activity. Fractionation of this high salt extract by sucrose density gradient centrifugation yielded a single peak of ATPase activity with an apparent sedimentation coefficient of 19 S. Electrophoretic analysis showed that this 19 S particle was composed of two heavy chains (termed alpha and beta; Mr 430,000 and 415,000, respectively), five intermediate molecular weight chains (IC1-IC5; Mr 85,000, 73,000, 65,000, 63,000, and 57,000), and six light chains (LC1-LC6; Mr 22,000-6,000). A similar complex was obtained following further purification by DEAE-Sephacel column chromatography. Quantitative densitometry of Coomassie Blue-stained gels indicated that the heavy and intermediate chains were present in equimolar amounts. Electron microscopic examination of the 19 S particles revealed that it consisted of two globular heads joined together by a Y-shaped stem. The 19 S particle had a specific MgATPase activity of 1.1 +/- 0.3 mumol of phosphate released/min/mg and exhibited an apparent Km for MgATP2- of 40 +/- 16 microM. MnATP2- and CaATP2- were hydrolyzed at rates 100 and 80% that of MgATP2-, respectively. The Mg-ATPase activity was inhibited by vanadate, but not by ouabain or oligomycin, and exhibited a high activity between pH 7.0 and 10.0 with a maximum at pH 9.0-9.5. ATP was the preferred nucleotide, although GTP and CTP (but not ITP) did interact with the dynein to a minor extent. Based on its origin, sedimentation coefficient, polypeptide composition, and enzymatic properties, we conclude that this two-headed 19 S particle represents the entire trout sperm axonemal outer arm dynein. This dynein is probably exemplary of the outer arm dyneins of other vertebrates.
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Purification and characterization of Salmo gairdneri outer arm dyneinDyneins are multimeric ATPases, which make up the inner and outer arms that bridge the outer doublet microtubules of eukaryotic cilia and flagella. They are responsible for the generation of sliding between outer doublets, which in turn is the basis for the formation and propagation of bending waves in both cilia and flagella. Outer arm dyneins are composed of two to three ATPases of Mr > 400,000, referred to as the α, β, and, where appropriate, γ heavy chains. Trout sperm is a new source of vertebrate dynein. Sperm can be repeatedly obtained in large quantities from the same trout (up to 4 × 10 spermatozoa per ejaculate), their axonemes can be readily isolated, and the dynein can be extracted efficiently and without significant proteolytic degradation. The advantages of trout sperm have permitted the detailed characterization of trout outer arm dynein to progress rapidly, so that it is now one of the best characterized of all dyneins. This chapter presents an overview of trout physiology and spermatogenesis for those not well acquainted with teleost physiology and anatomy and describes the methods for purification and characterization of Salmo gairdneri outer arm dynein.