Bent の走行によるフィラメントの運動

抄録

On the basis of our studies of the mechanochemistry of muscle protein actin, a model is proposed for the motile protein filament. The model consists of a large number of structural units and assemes a straight form, (F)_n, in its stable state. When the filament is subjected to a bending moment, it is bent at one position as a result of the partial breakage of a unit i, F_i→f_i. It is assumed that the reformation, f_i→F_i, takes place impulsively through a process which accompanies an irreversible chemical change in the medium. The active transformation, f_i→F_i, will induce a partial breakage F_j→f_j at another position, because the rapid reformation of the bent filament must be subject to a large viscous friction. It is assumed that, due to the polarity of the filament, the partial breakage, F_j→f_j occurs in a definite direction, j=i+1. The bent will propagate on the filament with the consumption of chemical energy.
A simple hydrodynamic analysis is made for such a motile protein filament in a viscous medium. The calculation is made according to Gray and Hancock. Three typtcal examples are treated; (a) The filament is fixed at one end and bent propagates from the base (b) the filament takes a form of regular polygon, and (c) the filament placed free in the medium.