help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Peyser, Y. M.
Right arrow Articles by Muhlrad, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Peyser, Y. M.
Right arrow Articles by Muhlrad, A.

Biophys J, August 2001, p. 1101-1114, Vol. 81, No. 2

Effect of Ionic Strength on the Conformation of Myosin Subfragment 1-Nucleotide Complexes

Y. Michael Peyser,* Katalin Ajtai,dagger Thomas P. Burghardt,dagger and Andras Muhlrad*

 *Hebrew University Hadassah School of Dental Medicine, Institute of Dental Sciences, Department of Oral Biology, Jerusalem 91120, Israel and  dagger Department of Biochemistry and Molecular Biology, Mayo Foundation, Rochester, Minnesota 55905 USA

The effect of ionic strength on the conformation and stability of S1 and S1-nucleotide-phosphate analog complexes in solution was studied. It was found that increasing concentration of KCl enhances the reactivity of Cys707 (SH1 thiol) and Lys84 (reactive lysyl residue) and the nucleotide-induced tryptophan fluorescence increment. In contrast, high KCl concentration lowers the structural differences between the intermediate states of ATP hydrolysis in the vicinity of Cys707, Trp510 and the active site, possibly by increasing the flexibility of the molecule. High concentrations of neutral salts inhibit both the formation and the dissociation of the M**.ADP.Pi analog S1.ADP.Vi complex. High ionic strength profoundly affects the structure of the stable S1.ADP.BeFx complex, by destabilizing the M*.ATP intermediate, which is the predominant form of the complex at low ionic strength, and shifting the equilibrium to favor the M**.ADP.Pi state. The M*.ATP intermediate is destabilized by perturbation of ionic interactions possibly by disruption of salt bridges. Two salt-bridge pairs, Glu501-Lys505 in the Switch II helix and Glu776-Lys84 connecting the catalytic domain to the lever arm, seem most appropriate to consider for participating in the ionic strength-induced transition of the open M*.ATP to the closed M**.ADP.Pi state of S1.

Biophys J, August 2001, p. 1101-1114, Vol. 81, No. 2
© 2001 by the Biophysical Society   0006-3495/01/08/1101/14  $2.00


This article has been cited by other articles:


Home page
 Biophys. JHome page
M. F. Halstead, K. Ajtai, A. R. Penheiter, J. D. Spencer, Y. Zheng, E. A. Morrison, and T. P. Burghardt
An Unusual Transduction Pathway in Human Tonic Smooth Muscle Myosin
Biophys. J., November 15, 2007; 93(10): 3555 - 3566.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
T. P. Burghardt, K. Ajtai, D. K. Chan, M. F. Halstead, J. Li, and Y. Zheng
GFP-Tagged Regulatory Light Chain Monitors Single Myosin Lever-Arm Orientation in a Muscle Fiber
Biophys. J., September 15, 2007; 93(6): 2226 - 2239.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
D. R. Davydov, A. E. Botchkareva, N. E. Davydova, and J. R. Halpert
Resolution of Two Substrate-Binding Sites in an Engineered Cytochrome P450eryF Bearing a Fluorescent Probe
Biophys. J., July 1, 2005; 89(1): 418 - 432.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2001 by the Biophysical Society.