The Polmerization of Actin: Thermodynamics Near the Polymeriztion Line

Published

August 1, 2003

Author(s)

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

Abstract

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.

Citation

Journal of Chemical Physics

Volume

119

Issue

No. 7

Pub Type

Journals

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Keywords

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

Citation

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], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852220 (Accessed October 13, 2025)