‘Freezing’ of Ca-regulated conformation of reconstituted thin filament of skeletal muscle by glutaraldehyde


REGULATION of skeletal muscle contraction by calcium ions is mediated by the troponin–tropomyosin system located in the groove of actin double strands1. Acting with tropomyosin, troponin depresses the ability of the actin filament to interact with the myosin molecule in the presence of ATP. Some structural changes in the thin filament associated with this depression have been detected by physical techniques2–8. When the actin filament is cross-linked with glutaraldehyde, it retains the ability to activate myosin ATPase9, and troponin and tropomyosin can no longer exert their regulatory effect on these cross-linked or ‘frozen’ actin filaments10. Using glutaraldehyde as cross-linking agent we have now been able to ‘freeze’ the activated (presence of calcium) and depressed (absence) states of the actin filament induced by the troponin–tropomyosin system: this suggests that the structural changes detected using physical methods are essential for regulation by calcium.

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  1. 1

    Ebashi, S., Endo, M. & Ohtsuki, I. Q. Rev. Biophys. 2, 351–384 (1969).

    CAS  Article  Google Scholar 

  2. 2

    Vibert, P. J., Haselgrove, J. C., Lowy, J. & Poulsen, F. R. J. molec. Biol. 71, 757–767 (1972).

    CAS  Article  Google Scholar 

  3. 3

    Haselgrove, J. C. Cold Spring Harb. Symp. quant. Biol. 37, 341–352 (1972).

    Article  Google Scholar 

  4. 4

    Huxley, H. E. Cold Spring Harb. Symp. quant. Biol. 37, 361–376 (1972).

    Article  Google Scholar 

  5. 5

    Parry, D. A. D. & Squire, J. M. J. molec. Biol. 75, 33–35 (1973).

    CAS  Article  Google Scholar 

  6. 6

    Yanagida, T., Taniguchi, M. & Oosawa, F. J. molec. Biol. 90, 509–522 (1974).

    CAS  Article  Google Scholar 

  7. 7

    Wakabayashi, T., Huxley, H. E., Amos, L. A. & Klug, A. J. molec. Biol. 93, 477–497 (1975).

    CAS  Article  Google Scholar 

  8. 8

    Gillis, J. M. & O'Brien, E. J. J. molec. Biol. 99, 445–459 (1975).

    CAS  Article  Google Scholar 

  9. 9

    Gadasi, H., Oplatka, A., Lamid, R., Hochberg, A. & Low, W. Biochim. biophys. Acta 33, 161–168 (1974).

    Article  Google Scholar 

  10. 10

    Poo, W-J. & Hartshorne, D. J. Biochem. biophys. Res. Commun. 70, 406–412 (1976).

    CAS  Article  Google Scholar 

  11. 11

    Mikawa, T. J. Biochem. (in the press).

  12. 12

    Ebashi, S., Toyo-oka, T. & Nonomura, Y. J. Biochem. 78, 859–861 (1975).

    CAS  Article  Google Scholar 

  13. 13

    Ebashi, S., Mikawa, T., Hirata, M., Toyo-oka, T. & Nonomura, Y. in Excitation–Contraction Coupling in Smooth Muscle (eds Casteels, R. et al.) 325–334 (North-Holland, Amsterdam, 1977).

    Google Scholar 

  14. 14

    Mikawa, T., Toyo-oka, T., Nonomura, Y. & Ebashi, S. J. Biochem. 81, 273–275 (1977).

    CAS  Article  Google Scholar 

  15. 15

    Laemmli, U. K. Nature 227, 680–685 (1970).

    ADS  CAS  Article  Google Scholar 

  16. 16

    Youngburg, G. E. & Youngburg, M. V. J. Lab. clin. Med. 16, 158–168 (1930).

    CAS  Google Scholar 

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MIKAWA, T. ‘Freezing’ of Ca-regulated conformation of reconstituted thin filament of skeletal muscle by glutaraldehyde. Nature 278, 473–474 (1979). https://doi.org/10.1038/278473a0

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