Simultaneous measurement of rotations of myosin, actin and ADP in a contracting skeletal muscle fiber

A. A. Shepard, D. Dumka, I. Akopova, J. Talent, Julian Borejdo

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The rotation of myosin heads and actin were measured simultaneously with an indicator of the enzymatic activity of myosin. To minimize complications due to averaging of signals from many molecules, the signal was measured in a small population residing in a femtoliter volume of a muscle fiber. The onset of rotation was synchronized by a sudden release of caged ATP. The orientation of cross-bridges was measured by anisotropy of recombinant fluorescent regulatory light chains exchanged with native regulatory light chains. The orientation of actin was measured by anisotropy of phalloidin added to actin filaments. The enzymatic activity of myosin was measured by dissociation of fluorescent ADP from the active site. The onset of all three events occurred at the same time. This suggests that in contracting muscle, actin does not move independently of myosin and that ATP hydrolysis is strongly coupled to the rotation of cross-bridges.

Original languageEnglish
Pages (from-to)549-557
Number of pages9
JournalJournal of Muscle Research and Cell Motility
Volume25
Issue number7
DOIs
StatePublished - 1 Dec 2004

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Skeletal Muscle Fibers
Myosins
Muscle
Actins
Fibers
Anisotropy
Phalloidine
Light
Muscles
Actin Cytoskeleton
Adenosine Diphosphate
Hydrolysis
Catalytic Domain
Adenosine Triphosphate
Molecules
ADP-G-actin
Population

Cite this

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Simultaneous measurement of rotations of myosin, actin and ADP in a contracting skeletal muscle fiber. / Shepard, A. A.; Dumka, D.; Akopova, I.; Talent, J.; Borejdo, Julian.

In: Journal of Muscle Research and Cell Motility, Vol. 25, No. 7, 01.12.2004, p. 549-557.

Research output: Contribution to journalArticle

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AU - Shepard, A. A.

AU - Dumka, D.

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AU - Talent, J.

AU - Borejdo, Julian

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