Actin polymerization under pressure: a theoretical study.
An extended Flory-Huggins-type equilibrium polymerization theory for compressible systems is used to describe experimental data for the unusual pressure and temperature dependence of the equilibrium polymerization of G-actin to F-actin. The calculations provide rich insights into the reaction mechanism and the thermodynamics of actin polymerization at the molecular level. Volume changes associated with individual steps of the mechanism are calculated to be DeltaVactiv=(s1*-s1)upsilon0=+1553 mlmol for the activation reaction, DeltaVdim=(s2-s1*)upsilon0=-3810 mlmol for dimerization, and DeltaVprop=(sP-s1)upsilon0=+361 mlmol for the propagation reaction, where s1upsilon0, s1*upsilon0, s2upsilon0, and sPupsilon0 are the monomer volumes in the G-actin monomer, the activated G-action, the dimer, and higher polymers, respectively. Comparison with experimental measurements is made, and discrepancies are discussed.
Artyomov
Maxim N
MN
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Freed
Karl F
KF
D008841:Actin Cytoskeleton / Q000737:chemistry*; D000199:Actins / Q000737:chemistry* / Q000648:ultrastructure*; D001665:Binding Sites; D001704:Biopolymers / Q000737:chemistry*; D003198:Computer Simulation; D008956:Models, Chemical; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry / Q000648:ultrastructure; D011312:Pressure; D011485:Protein Binding; D011487:Protein Conformation
D000199:Actins; D001704:Biopolymers; D046912:Multiprotein Complexes