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 Nitao, L. K.
Right arrow Articles by Reisler, E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Nitao, L. K.
Right arrow Articles by Reisler, E.

Biophys J, June 2000, p. 3072-3080, Vol. 78, No. 6

Actin and Temperature Effects on the Cross-Linking of the SH1-SH2 Helix in Myosin Subfragment 1

Lisa K. Nitao and Emil Reisler

Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California, Los Angeles, California 90095 USA

Past biochemical work on myosin subfragment 1 (S1) has shown that the bent alpha -helix containing the reactive thiols SH1 (Cys707) and SH2 (Cys697) changes upon nucleotide and actin binding. In this study, we investigated the conformational dynamics of the SH1-SH2 helix in two actin-bound states of myosin and examined the effect of temperature on this helix, using five cross-linking reagents that are 5-15 Å in length. Actin inhibited the cross-linking of SH1 to SH2 on both S1 and S1.MgADP for all of the reagents. Because the rate of SH2 modification was not altered by actin, the inhibition of cross-linking must result from a strong stabilization of the SH1-SH2 helix in the actin-bound states of S1. The dynamics of the helix is also influenced by temperature. At 25°C, the rate constants for cross-linking in S1 alone are low, with values of ~0.010 min-1 for all of the reagents. At 4°C, the rate constants, except for the shortest reagent, range between 0.030 and 0.070 min-1. The rate constants for SH2 modification in SH1-modified S1 show the opposite trend; they increase with the increases in temperature. The greater cross-linking at the lower temperature indicates destabilization of the SH1-SH2 helix at 4°C. These results are discussed in terms of conformational dynamics of the SH1-SH2 helix.

Biophys J, June 2000, p. 3072-3080, Vol. 78, No. 6
© 2000 by the Biophysical Society   0006-3495/00/06/3072/09  $2.00


This article has been cited by other articles:


Home page
 Biophys. JHome page
B. Liu, C. J. Goergen, and J.-Y. Shao
Effect of Temperature on Tether Extraction, Surface Protrusion, and Cortical Tension of Human Neutrophils
Biophys. J., October 15, 2007; 93(8): 2923 - 2933.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
L. K. Nitao, T. O. Yeates, and E. Reisler
Conformational Dynamics of the SH1-SH2 Helix in the Transition States of Myosin Subfragment-1
Biophys. J., November 1, 2002; 83(5): 2733 - 2741.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2000 by the Biophysical Society.