Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Conformational selection during weak binding at the actin and myosin interface.

J Xu1, D D Root

  • 1Department of Biological Sciences, University of North Texas, Denton, Texas 76203-5220 USA.

Biophysical Journal
|September 2, 2000
PubMed
Summary

Muscle contraction

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

High-affinity actin-binding nebulin fragments influence the actoS1 complex.

Biochemistry·2001
Same author

Modulation of troponin T molecular conformation and flexibility by metal ion binding to the NH2-terminal variable region.

Biochemistry·2000
Same author

Native purification of biomolecules with temperature-mediated hydrophobic modulation liquid chromatography.

Analytical biochemistry·2000
Same author

Determination of fluorescent probe orientations on biomolecules by conformational searching: algorithm testing and applications to the atomic model of myosin.

Journal of structural biology·1999
Same author

Domain motion between the regulatory light chain and the nucleotide site in skeletal myosin.

Journal of structural biology·1998
Same author

Dynamic cross-linking by alpha-actinin determines the mechanical properties of actin filament networks.

The Journal of biological chemistry·1998

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Muscle Physiology

Background:

  • The myosin motor's powerstroke is crucial for muscle contraction.
  • Previous models proposed significant myosin head rotation during the powerstroke.

Purpose of the Study:

  • To investigate the molecular mechanism of the myosin powerstroke.
  • To test models involving large myosin head rotations and actin participation.

Main Methods:

  • Resonance energy transfer (RET) techniques were used to measure distances within myosin and between myosin and actin.
  • Nucleotide transition state analogs were employed to trap specific myosin states.
  • Stopped-flow RET monitored ATP turnover during single cycles.

Main Results:

  • Only minor conformational changes (<0.5 nm) were observed in myosin, contradicting models of large lever arm rotations.
  • RET efficiency between myosin and actin was significantly higher with ADP-bound transition state analogs (ADP-AlF4, ADP-BeFx, ADP-vanadate) compared to ADP alone.
  • These findings indicate distinct conformations for weakly and strongly bound cross-bridges.

Conclusions:

  • The myosin powerstroke involves internal conformational changes rather than extreme lever arm rotations.
  • Actin binding induces significant conformational changes in myosin, likely through a conformational selection mechanism during weak binding.
  • Understanding these conformational dynamics is key to elucidating muscle contraction.

Related Experiment Videos