EXAMINATION OF TEMPERATURE-INDUCED GEL-SOL TRANSFORMATION OF ALPHA-ACTININ CROSS-LINKED ACTIN NETWORKS BY STATIC LIGHT-SCATTERING/

We studied the gel-sol transformation of F-actin/alpha-actinin solutio ns. 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 conc entration, [A], and reduction of actin filament lengths, r(AG), augmen t the maximal light intensity, I and shift the gel-sol transition poin t, T-g to higher temperatures. This behavior is interpreted in terms o f the model developed by Tempel, M., Isenberg, G. and Sackmann, E. (19 96) (Physical Review E 54, 1802-1810) based on the percolation theory. Using the temperature-dependent binding model of this theory allows i nstant prediction of the equilibrium constant, K for F-actin/alpha-act inin solutions at temperatures T< T-g. (C) 1998 Federation of European Biochemical Societies.