Abstract
The low-angle equatorial X-ray reflections from the filament lattice of vertebrate striated muscle have been investigated as a function of sarcomere length and the nature of the bathing medium. In glycerinated (rabbit psoas) muscle, the lattice dimension was found to be a function of sarcomere length, and the pH, ionic strength and valency of cations in the inter-filament medium. The total variation of the myosin—myosin centre-to-centre separation according to these parameters was 370 to 570 Å. Similar effects were also demonstrated in living (toad sartorius) muscle: the myosin—myosin centre-to-centre separation varied between 310 and 510 Å according to the sarcomere length, and the pH and ionic strength of the bathing medium. The dependence of the filament separation on the electrical parameters of the inter-filament medium indicates that there are long-range electrostatic forces between the filaments. It is suggested that the contractile apparatus of muscle behaves as a colloid in which the separation of the filaments is determined by the balance of electrostatic double-layer repulsive forces and van der Waals' attractive forces.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call