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A kinetic comparison between Mg-actin and Ca-actin

Summary

The kinetics of the elongation reaction in the polymerization of actin containing tightly-bound Mg2+ (Mg-actin) or tightly-bound Ca2+ (Ca-actin) have been studied. The reaction was monitored using the increase in fluorescence intensity ofN-(1-pyrenyl)iodoacetamide-labelled monomeric actin as a measure of polymer formation. The actin nucleation reaction was circumvented by the addition of phalloidin-stabilized actin nuclei. Elongation rates were obtained at various actin concentrations and at various temperatures for polymerization induced by the presence of different monovalent and divalent salt concentrations. Values for the relative rate constant of forward polymerization (mk +) for Mg-actin were found to be larger than those for Ca-actin under similar conditions (m=number of polymer ends). The critical actin concentration (c c ) of Mg-actin is lower than thec c for Ca-actin, as were estimates of the relative rate constant of depolymerization (mk ). The temperature dependence ofc c ,mk + andmk for Mg-actin was different from that for Ca-actin, further suggesting a difference in monomeric properties due to the type of divalent cation tightly bound to actin. Estimates of the activation enthalpy change for the forward reaction in the G ⇄ F transformation were similar for both types of actin, but the activation enthalpy change for the depolymerization of Mg-actin was significantly larger than that for Ca-actin.

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References

  • Asakura, S., Kasai, M. &Oosawa, F. (1960) The effect of temperature on the equilibrium state of actin solutions.J. Polymer Sci. 44, 35–49.

    Google Scholar 

  • Bergen, L. G. &Borisy, G. G. (1980) Head-to-tail polymerization of microtubulesin vitro. J. Cell. Biol. 84, 141–50.

    Google Scholar 

  • Clarke, M. &Spudich, J. A. (1977) Non-muscle contractile proteins.A. Rev. Biochem. 96, 797–822.

    Google Scholar 

  • Cooper, J. A., Buhle, E.,Jr., Walker, S. B., Tsong, T. Y. &Pollard, T. D. (1983) Kinetic evidence for a monomer activation step in actin polymerization.Biochemistry 22, 2193–202.

    Google Scholar 

  • Estes, J. E., Selden, L. A. &Gershman, L. C. (1981) Mechanism of action of phalloidin on the polymerization of muscle actin.Biochemistry 20, 708–12.

    Google Scholar 

  • Frieden, C. (1982) The Mg++-induced conformational change in rabbit skeletal muscle.J. biol. Chem. 257, 2882–6.

    Google Scholar 

  • Frieden, C., Lieberman, D. &Gilbert, H. R. (1980) A fluorescent probe for conformational changes in skeletal muscle G-actin.J. biol. Chem. 255, 8991–3.

    Google Scholar 

  • Gershman, L. C., Estes, J. E. &Selden, L. A. (1984a) Actin polymerization is regulated by the tightly bound divalent cation.Ann. N.Y. Acad Sci. 435, 151–3.

    Google Scholar 

  • Gershman, L. C., Newman, J., Selden, L. A. &Estes, J. E. (1984b) Bound-cation exchange affects the lag phase in actin polymerization.Biochemistry 23, 2199–203.

    Google Scholar 

  • Gordon, D. J., Yang, Y.-Z. &Korn, E. D. (1976) Polymerization ofAcanthameoba actin.J. biol. Chem. 251, 7474–9.

    Google Scholar 

  • Kasai, M. (1969) Thermodynamic aspect of G-F transformation of actin.Biochim. biophys. Acta 180, 399–409.

    Google Scholar 

  • Kasai, M., Asakura, S. &Oosawa, F. (1962) The cooperative nature of G-F transformation of actin.Biochim. biophys. Acta 57, 22–31.

    Google Scholar 

  • Kasai, M. &Oosawa, F. (1968) The exchangeability of actin-bound calcium with various cations.Biochim. biophys. Acta 154, 520–8.

    Google Scholar 

  • Kasai, M. &Oosawa, F. (1969) Behavior of divalent cations and nucleotide bound to F-actin.Biochim. biophys. Acta 172, 300–10.

    Google Scholar 

  • Kitazawa, T., Shuman, H. &Somlyo, A. P. (1982) Calcium and magnesium binding to thick and thin filaments in skinned muscle fibres: electron probe analysis.J. Musc. Res. Cell Motility 3, 437–54.

    Google Scholar 

  • Korn, E. D. (1982) Actin polymerization and its regulation by proteins from non-muscle cells.Physiol. Rev. 62, 672–737.

    Google Scholar 

  • Kouyama, T. &Mihashi, K. (1981) Fluorimetry study of N-(1-pyrenyl)iodoacetamide-labelled F-actin. Local structural change of actin protomer both on polymerization and on binding of heavy meromyosin.Eur. J. Biochem. 114, 33–8.

    Google Scholar 

  • Mihashi, K. &Ooi, T. (1965) Effects of divalent cations and ethanol on actin. InMolecular Biology of Muscular Contraction (edited byEbashi, S., Oosawa, F., Sekine, T. andTonomara, Y.), pp. 77–89. Tokyo: Igaku Shoin.

    Google Scholar 

  • Oosawa, F. (1983) Marcromolecular assembly of actin. InMuscle and Non-muscle Motility (edited byStracher, A.) pp. 151–216. New York: Academic Press.

    Google Scholar 

  • Oosawa, F. &Asakura, S. (1975)Thermodynamics of the Polymerization of Protein. New York: Academic Press.

    Google Scholar 

  • Oosawa, F., Asakura, S., Asai, H., Kasai, M., Kobayashi, S., Mihashi, K., Ooi, T., Tanagichi, M. &Nakano, E. (1964) Structure and function of actin polymers. InBiochemistry of Muscle Contraction (edited byGergely, J.) pp. 158–72. Boston: Little, Brown.

    Google Scholar 

  • Pollard, T. D., Aebi, V., Cooper, J. A., Fowler, W. E., Kiehart, D. P., Smith, P. R. &Tseng, P. C. (1982) Actin and myosin function inAcanthameoba.Phil, Trans. R. Soc. Lond. Ser. B. 299, 237–45.

    Google Scholar 

  • Pollard, T. D. &Mooseker, M. S. (1981) Direct measurement of actin polymerization rate constants by electron microscopy of actin filaments nucleated by isolated microvillus cores.J. Cell Biol. 88, 654–9.

    Google Scholar 

  • Pollard, T. D. &Weihing, R. R. (1974) Actin and myosin and cell movement.CRC Crit. Rev. Biochem. 2, 1–65.

    Google Scholar 

  • Rouayrenc, J.-F. &Travers, F. (1981) The first step in the polymerization of actin.Eur. J. Biochemistry 116, 73–7.

    Google Scholar 

  • Roustan, C., Benjamin, Y., Boyer, M., Bertrand, R., Andemard, E. &Jaruequi-Adell, J. (1985) Conformational changes induced by Mg++ on actin monomers.FEBS Lett. 181, 119–23.

    Google Scholar 

  • Selden, L. A., Estes, J. E. &Gershman, L. C. (1983) The tightly bound divalent cation regulates actin polymerization.Biochem. Biophys. Res. Commun. 116, 478–85.

    Google Scholar 

  • Spudich, J. A. &Watt, S. (1971) The regulation of rabbit skeletal muscle contraction.J. biol. Chem. 246, 4866–71.

    Google Scholar 

  • Szent-Györgyi, A. (1951)Chemistry of Muscular Contraction, 2nd edn. New York: Academic Press.

    Google Scholar 

  • Tobacman, L. &Korn, E. D. (1983) The kinetics of actin nucleation and polymerization.J. biol. Chem. 258, 3207–14.

    Google Scholar 

  • Weber, A., Herz, R. &Reiss, I. (1969) The role of magnesium in the relaxation of myofibrils.Biochemistry 8, 2266–71.

    Google Scholar 

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Selden, L.A., Gershman, L.C. & Estes, J.E. A kinetic comparison between Mg-actin and Ca-actin. J Muscle Res Cell Motil 7, 215–224 (1986). https://doi.org/10.1007/BF01753554

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  • DOI: https://doi.org/10.1007/BF01753554

Keywords

  • Polymer
  • Fluorescence Intensity
  • Salt Concentration
  • Similar Condition
  • Divalent Cation