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The Polmerization of Actin: Thermodynamics Near the Polymeriztion Line



P S. Niranjan, H Yim, D Forbes, S C. Greer, J Dudowicz, Karl Freed, Jack F. Douglas


We report here new measurements of the extent of polymerization of rabbit muscle actin as a function of T , initial G-actin concentration and initiating salt concentration, in both H2O and D2O buffers. These measurements are unique in being done as a function of T, near the floor temperature for polymerization, Tp, so that polymerization is initiated by T change, with the necessary salt being present in the initial sample. The measurements show that Tp decreases as either [G]0 or [KCl] increases, and that the extent of polymerization, M, as a function of T shows a maximum, indicating a re-entrant depolymerization at higher T. The measurements are interpreted in terms of a Flory-Huggins type lattice model that includes a monomer activation reaction, a dimerization of activated species, the formation of a trimer as the smallest propagating oligomer, and a propagation step.
Journal of Chemical Physics
No. 7


actin, associating polymer, deuteration effect, polymerization transition, proteins, re-enterant depolymerization, salt, thermodynamics


Niranjan, P. , Yim, H. , Forbes, D. , Greer, S. , Dudowicz, J. , Freed, K. and Douglas, J. (2003), The Polmerization of Actin: Thermodynamics Near the Polymeriztion Line, Journal of Chemical Physics, [online], (Accessed April 20, 2024)
Created July 31, 2003, Updated October 12, 2021