QUASI-ELASTIC LIGHT-SCATTERING OF SUSPENSIONS OF LIMULUS THICK MYOFILAMENTS IN RELAXED (LONG) ACTIVATED AND RERELAXED (SHORT) STATES

[摘要] Photoelectron count autocorrelation function of light scattered by Limulus thick myofilament suspensions was measured as a function of scattering angle in the relaxed, activated and rerelaxed stages. By using the cumulants method of data analysis, the average linewidth over large ranges of KL (up to 120), was calculated with K and L being, respectively, the magnitude of the momentum transfer vector and the length of the myofilament. A dramatic increase was observed in the average linewidth denoting the presence of additional high frequency components for the myofilament suspension on the activated state. By confirming the results on the size of the myofilaments from EM, the high frequency (kHz) components can be attributed to the correlated cross-bridge motions, representing the 1st direct experimental evidence of such movements in isolated thick myofilament suspensions.