Examination of temperature-induced 'gel-sol' transformation of α-actinin/cross-linked actin networks by static light scattering

We studied the gel-sol transformation of F-actin/alpha-actinin solutions. Gross-linking of actin filaments by a-actinin shows a temperature-dependent increase in light scatter signal, (I)T. Higher F-actin/alpha-actinin molar ratios, r(A alpha) as well as increases in F-actin concentration, [A], and reduction of actin filament lengths, r(AG), augment the maximal light intensity, I and shift the gel-sol transition point, T-g to higher temperatures. This behavior is interpreted in terms of the model developed by Tempel, M., Isenberg, G. and Sackmann, E. (1996) (Physical Review E 54, 1802-1810) based on the percolation theory. Using the temperature-dependent binding model of this theory allows instant prediction of the equilibrium constant, K for F-actin/alpha-actinin solutions at temperatures T< T-g. (C) 1998 Federation of European Biochemical Societies.