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Image Analysis of the Complex of Actin-Tropomyosin and Myosin Subfragment 1

  • Takeyuki Wakabayashi
  • Chikashi Toyoshima
  • Eisaku Katayama
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 37)

Abstract

  1. 1.

    A three-dimensional image of the “rigor” complex of actin-tropomyosin-S1 was reconstituted from both low dose (10 electrons/Å2) and high dose (>500 electrons/Å2) electron microscopic images of specimens embedded in unbroken and unbacked stain sheets of uranyl acetate over the holes of perforated carbon films.

     
  2. 2.

    Myosin S1 shows multi-domain submolecular structure as has been earlier observed in actin-S1 (Wakabayshi & Toyoshima, 1981) and actin-heavy mepomyosin (Katayama & Wakabayashi, 1981). The morphological unit of the actin-tropomyosin-S1 was found to be composed of at least three domains (domains A, B and D) and three regions (C, E and H).

     
  3. 3.

    A myosin S1 molecule has a complex shape, which cannot be represented by a simple rod with one major axis. The shape of S1 should be approximated by at least two rods.

     
  4. 4.

    The domain D is identified as the main part of S1. The angle between the major axis of this domain and the axis of actin helix was about 72°, which is almost right angle.

     
  5. 5.

    The angle between the axis of actin helix and major axis of the region E, which is less bulky than the domain D and makes no contact with actin, is much smaller than the value for the domain D.

     
  6. 6.

    The resolution of reconstituted images from both high and low dose micrographs was improved so that the radial resolution became about 15 Å and the axial one became about 25 Å. Due to the improvement of resolution in both the radial and axial direction, all major domains A, B and D split into two domains, i.e. into A1 and A2, B1 and B2, and D1 and D2 respectively.

     
  7. 7.

    Though unambiguous assignment of actin is not yet achieved by us, it can be confirmed that a S1 molecule interacts morphologically with actin at two sites (Wakabayashi & Toyoshima, 1981).

     

Keywords

Thin Filament Actin Monomer Type Assignment Myosin Molecule Helix Axis 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. DeRosier, D.J. & Moore, P.B. (1970). Reconstruction of three-dimensional images from electron micrographs of structures with helical symmetry. J. Mol. Biol. 52: 355–369.PubMedCrossRefGoogle Scholar
  2. Katayama, E. & Wakabayshi, T. (1981). Three-dimensional image analysis of the complex of thin filaments and myosin molecules from skeletal muscle. III. The multi-domain structure of actin-heavy meromyosin complex. J. Biochem. 90: 703–714.PubMedGoogle Scholar
  3. Moore, P.B., Huxley, H.E. & DeRosier, D.J. (1970). Three-dimensional reconstruction of Factin, thin filaments and decorated thin filaments. J. Mol. Biol. 50: 279–295.PubMedCrossRefGoogle Scholar
  4. Mornet, M., Bertrand, R, Pantel, P., Audemard, E. & Kassab, R. (1981). Structure of the actin-myosin interface. Nature 292: 301–306.PubMedCrossRefGoogle Scholar
  5. Seymour, J. & O’Brien, E.J. (1980). The position of tropomyosin in muscle thin filaments. Nature 283: 680–682.PubMedCrossRefGoogle Scholar
  6. Spudich, J.S., Huxley, H.E. & Finch, J.T. (1972). Regulation of skeletal muscle contraction. II. Structural studies of the interaction of the tropomyosin-troponin complex with actin. J. Mol. Biol. 72: 619–632.PubMedCrossRefGoogle Scholar
  7. Szent-Gyorgyi, A. (1951). Chemistry of Muscular Contraction, 2nd ed., Academic Press.Google Scholar
  8. Taylor, K.A. & Amos, L.A. (1981). A new model for the geometry of the binding of myosin crossbridges to muscle thin filaments. J. Mol. Biol. 147: 297–324.PubMedCrossRefGoogle Scholar
  9. Toyoshima, C. & Wakabayashi, T. (1979). Three-dimensional image analysis of the complex of thin filaments and myosin molecules from skeletal muscle. I. Tilt angle of myosin subfragment-1 in the rigor complex. J. Biochem. 86: 1887–1890.PubMedGoogle Scholar
  10. Vibert & Craig, R. (1982). Three-dimensional reconstruction of thin filaments decorated with a Cat+-regulated myosin. J. Mol. Biol. 157: 299–319.PubMedCrossRefGoogle Scholar
  11. Wakabayashi, T., Huxley, H.E., Amos, L.A. & Klug, A. (1975). Three-dimensional image reconstruction of actin-tropomyosin complex and actin-tropomyosin-troponin T-troponin I complex. J. Mol. Biol. 93: 477–497.PubMedCrossRefGoogle Scholar
  12. Wakabayashi, T. and Toyoshima, C. (1981). Three-dimensional image analysis of the complex of thin filaments and myosin molecules from skeletal muscle. U. The multi-domain structure of actin-myosin S1 complex. J. Biochem. 90: 683–701.PubMedGoogle Scholar

Copyright information

© Plenum Press, New York 1984

Authors and Affiliations

  • Takeyuki Wakabayashi
    • 1
  • Chikashi Toyoshima
    • 1
  • Eisaku Katayama
    • 2
  1. 1.Department of Physics, Faculty of ScienceUniversity of TokyoBunyo-ku, Tokyo 113Japan
  2. 2.Department of Pharmacology, Faculty of MedicineUniversity of TokyoBunyo-ku, Tokyo 113Japan

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