Affordable Access

Kinetics and thermodynamics of the assembly of the parallel- and antiparallel-packed sections of synthetic thick filaments of skeletal myosin: a pressure-jump study.

Authors
Type
Published Article
Journal
Biochemistry
0006-2960
Publisher
American Chemical Society
Publication Date
Volume
24
Issue
19
Pages
5263–5269
Identifiers
PMID: 4074693
Source
Medline

Abstract

Earlier work on the length regulation mechanism of synthetic myosin filaments generated at pH 8.2 showed the process to be mediated through the dissociation rate constant which had an increasing and apparently monophasic exponential dependence on filament length and an association rate constant that was length independent, filament growth ceasing at the point of equilibrium [Davis, J.S. (1981) Biochem. J. 197, 309-314]. In this work, the exponential dependence of the dissociation rate constant on thick filament length was shown to be more complex than originally thought. Two phases were resolved, one of which correlated with the dissociation of parallel-packed myosin and the other with that of antiparallel-packed material. The pressure dependence of the dissociation reaction for the parallel-packed material showed that the activation volume decreased linearly with length while the Gibbs energy increased. This was interpreted as indicating that the weakening of the interaction between dimer and filament with length was accompanied by a decrease in the extent of ionic bonding. The case in the antiparallel-packed region was quite different, with the activation volume and the Gibbs energy both increasing linearly. The contribution from ionic bonding thus rises counter to the change in Gibbs energy, presumably at the expense of other noncovalent interactions. The relationship between the synthetic thick filaments and their in vivo counterparts is also considered in some detail.

There are no comments yet on this publication. Be the first to share your thoughts.

Statistics

Seen <100 times
0 Comments
F