Journal of Molecular Biology
Volume 224, Issue 4, 20 April 1992, Pages 1029-1038
Journal home page for Journal of Molecular Biology

Article
Temperature dependence and arrhenius activation energy of F-actin velocity generated in vitro by skeletal myosin

https://doi.org/10.1016/0022-2836(92)90467-XGet rights and content

Abstract

The effect of temperature on the velocity of rhodamine phalloidin-labelled F-actin moving in vitro on rabbit skeletal myosin has been studied. Translating actin filaments were visualized by epi-fluorescence in an inverted microscope, equipped with temperature control (±0·2 K) of the stage and objective. Images were recorded in real time at magnifications of 400 × or 160 × by an intensified CCD camera on video tape. Motion of individual filaments was tracked by hand and velocities determined using frame times recorded simultaneously on the video tape. Velocity changed from 12 μm per second at 42 °C to 11 nm per second at 3 °C. The Arrhenius plot is non-linear, with the data following a cubic regression curve with no evident breaks or jumps. Data taken over the temperature range from single preparations followed the same curve for both heating and cooling; this indicates reversibility and absence of hysteresis. A hyperbolic model that smoothly translates with temperature between two asymptotic activation energies fits the data above 7 °C: these energies are 50(±5) kJ per mole (Q10 = 1·9) at high temperatures and 289(±29) kJ per mole (Q10 = 76·5) at low temperature with a transition temperature of 15·4(±0.6) °C. These values are compared with other measurements made in vitro, in solution studies and on muscle fibres. An Arrhenius activation energy of 50 kJ per mole and a transition temperature of 15 °C are consistent with previous determinations but 289 kJ per mole is significantly greater than has been seen at low temperatures in other systems. This may indicate a different rate-limiting step in the kinetics of skeletal myosin driving actin filaments in vitro below 15 °C. Current determinations of the myosin “step-size” assume that the actin velocity is determined by the rate of ATP hydrolysis; the data confirm similar activation energies above 20 °C but they show that the temperature dependencies and activation energies are different at lower temperatures, implying uncoupling of the two processes.

References (36)

  • M. Anson

    Temperature dependence of the velocity of fluorescently labelled F-actin sliding on rabbit skeletal myosin in vitro

    J. Physiol

    (1991)
  • M. Bárány

    ATPase activity of myosin correlated with speed muscle shortening

    J. Gen. Physiol

    (1967)
  • J.A. Biocsa et al.

    A jump in the Arrhenius plot can be the consequence of a phase transition

    FEBS Letters

    (1983)
  • J.A. Biosca et al.

    Cryoenzymic studies on myosin subfragment 1: peturbation of an enzyme reaction by temperature and solvent

    Biochemistry

    (1984)
  • H. Faulstich et al.

    Fluorescent phallotoxins as probes for filamentous actin

    J. Musc. Res. Cell Motil

    (1988)
  • H. Gutfreund
  • Y. Harada et al.

    Sliding movement of single actin filaments on one-headed myosin filaments

    Nature (London)

    (1987)
  • M.G. Hibberd et al.

    Relationships between chemical and mechanical events during muscular contraction

    Annu. Rev. Biophys. Biophys. Chem

    (1986)
  • Cited by (0)

    View full text