ArticleBiophysical journal2007
Stiffness and fraction of Myosin motors responsible for active force in permeabilized muscle fibers from rabbit psoas.
Article in Biophysical journal, 2007. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 99 papers.
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99 citing papers in PubMed, 161 citations in OpenAlex.
- Isometric slow- and fast-contracting skeletal muscle fibres have more similar cellular and molecular properties at 37°C than at 25°C in older adults.The Journal of physiology · 2026Article
- Effects of chemical myosin II cross-bridge inhibitors on eccentric force production in skinned muscle fibres.Experimental physiology · 2026Article
- Subsarcomeric regulation of thin and thick filaments in skeletal muscle myofibrils.Proceedings of the National Academy of Sciences of the United States of America · 2026Article
- A primer on the methods of skeletal and cardiac muscle mechanics using permeabilized preparations.The Journal of general physiology · 2026Review
- Consecutive SSCs increase the SSC effect in skinned rat muscle fibres.Pflugers Archiv : European journal of physiology · 2025Article
- Resolving the kinetics of an ensemble of muscle myosin motors via a temperature-dependent fitting procedure.Journal of the Royal Society, Interface · 2025Article
- The Mechanism of Modulation of Cardiac Force by Temperature.International journal of molecular sciences · 2025Article
- Multiple pathways of the actin-myosin cycle in energy transduction and the release of orthophosphate in muscle.Frontiers in physiology · 2025Review
- Impact of lengthening velocity on the generation of eccentric force by slow-twitch muscle fibers in long stretches.Pflugers Archiv : European journal of physiology · 2024Article
- The carbon monoxide prodrug oCOm-21 increases CaPhysiological reports · 2024Article
- Dependence of myosin filament structure on intracellular calcium concentration in skeletal muscle.The Journal of general physiology · 2023Article
- Matching Mechanics and Energetics of Muscle Contraction Suggests Unconventional Chemomechanical Coupling during the Actin-Myosin Interaction.International journal of molecular sciences · 2023Article
- A century of exercise physiology: key concepts in muscle energetics.European journal of applied physiology · 2023Review
- Muscle preflex response to perturbations in locomotion:Frontiers in bioengineering and biotechnology · 2023Article
- Ultrastructural and kinetic evidence support that thick filaments slide through the Z-disc.Journal of the Royal Society, Interface · 2022Article
- The force of the myosin motor sets cooperativity in thin filament activation of skeletal muscles.Communications biology · 2022Article
- Anisotropic Elasticity of the Myosin Motor in Muscle.International journal of molecular sciences · 2022Article
- Myosin-based regulation of twitch and tetanic contractions in mammalian skeletal muscle.eLife · 2021Article
- Dependence of thick filament structure in relaxed mammalian skeletal muscle on temperature and interfilament spacing.The Journal of general physiology · 2021Article
- Power Amplification Increases With Contraction Velocity During Stretch-Shortening Cycles of Skinned Muscle Fibers.Frontiers in physiology · 2021Article
39 more citing papers are in PubMed but not listed here.
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Authors and funding
5 authors at 3 institutions in 2 countries.
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Abstract
The stiffness of the single myosin motor (epsilon) is determined in skinned fibers from rabbit psoas muscle by both mechanical and thermodynamic approaches. Changes in the elastic strain of the half-sarcomere (hs) are measured by fast mechanics both in rigor, when all myosin heads are attached, and during active contraction, with the isometric force (T0) modulated by changing either [Ca2+] or temperature. The hs compliance is 43.0+/-0.8 nm MPa-1 in isometric contraction at saturating [Ca2+], whereas in rigor it is 28.2+/-1.1 nm MPa-1. The equivalent compliance of myofilaments is 21.0+/-3.3 nm MPa-1. Accordingly, the stiffness of the ensemble of myosin heads attached in the hs is 45.5+/-1.7 kPa nm-1 in isometric contraction at saturating [Ca2+] (e0), and in rigor (er) it rises to 138.9+/-21.2 kPa nm-1. Epsilon, calculated from er and the lattice molecular dimensions, is 1.21+/-0.18 pN nm-1. epsilon estimated, using a thermodynamic approach, from the relation of T0 at saturating [Ca2+] versus the reciprocal of absolute temperature is 1.25+/-0.14 pN nm-1, similar to that estimated for fibers in rigor. Consequently, the ratio e0/er (0.33+/-0.05) can be used to estimate the fraction of attached heads during isometric contraction at saturating [Ca2+]. If the osmotic agent dextran T-500 (4 g/100 ml) is used to reduce the lateral filament spacing of the relaxed fiber to the value before skinning, both e0 and er increase by approximately 40%. Epsilon becomes approximately 1.7 pN nm-1 and the fraction and the force of myosin heads attached in the isometric contraction remain the same as before dextran application. The finding that the fraction of myosin heads attached to actin in an isometric contraction is 0.33 rules out the hypothesis of multiple mechanical cycles per ATP hydrolyzed.
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