|
|
||||||||
Departments of 1 Radiology, 2 Physiology and Biophysics, and 3 Zoology, University of Washington, Seattle, Washington 98195
We tested the hypothesis that solvent viscosity affects translocation of rhodamine phalloidin-labeled F-actin by rabbit skeletal heavy meromyosin (HMM). When viscosity was increased using either glycerol, fructose, sucrose, or dextran (1.5, 6.0, or 15-20 kDa mol mass), there was little or no effect on the fraction of moving filaments, whereas sliding speed decreased in inverse proportion to viscosity. The results could be explained neither by an effect of osmotic pressure at high solute concentrations nor by altered solvent drag on the actin filament. Elevated viscosity inhibited HMM ATPase activity in solution, but only at much higher viscosities than were needed to reduce sliding speed. Polyethylene glycols (300, 1,000, or 3,000 mol wt) also inhibited speed via elevated viscosity but secondarily inhibited by enhancing electrostatic interactions. These results demonstrate that a diffusion-controlled process intrinsic to cross-bridge cycling can be limiting to actomyosin function.
in vitro motility assay; protein dynamics of biological motors; diffusion; sugars; polyethylene glycols
This article has been cited by other articles:
![]() |
B. Schoffstall, N. M. Brunet, S. Williams, V. F. Miller, A. T. Barnes, F. Wang, L. A. Compton, L. A. McFadden, D. W. Taylor, M. Seavy, et al. Ca2+ sensitivity of regulated cardiac thin filament sliding does not depend on myosin isoform J. Physiol., December 15, 2006; 577(3): 935 - 944. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Schoffstall, A. Clark, and P. B. Chase Positive Inotropic Effects of Low dATP/ATP Ratios on Mechanics and Kinetics of Porcine Cardiac Muscle Biophys. J., September 15, 2006; 91(6): 2216 - 2226. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. W. Clemmens, M. Entezari, D. A Martyn, and M. Regnier Different effects of cardiac versus skeletal muscle regulatory proteins on in vitro measures of actin filament speed and force J. Physiol., August 1, 2005; 566(3): 737 - 746. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Schoffstall, A. Kataoka, A. Clark, and P. B. Chase Effects of Rapamycin on Cardiac and Skeletal Muscle Contraction and Crossbridge Cycling J. Pharmacol. Exp. Ther., January 1, 2005; 312(1): 12 - 18. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Liang, Y. Chen, C.-K. Wang, Z. Luo, M. Regnier, A. M. Gordon, and P. B. Chase Ca2+ Regulation of Rabbit Skeletal Muscle Thin Filament Sliding: Role of Cross-Bridge Number Biophys. J., September 1, 2003; 85(3): 1775 - 1786. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Kohler, Y. Chen, B. Brenner, A. M. Gordon, T. Kraft, D. A. Martyn, M. Regnier, A. J. Rivera, C.-K. Wang, and P. B. Chase Familial hypertrophic cardiomyopathy mutations in troponin I (K183{Delta}, G203S, K206Q) enhance filament sliding Physiol Genomics, July 7, 2003; 14(2): 117 - 128. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |