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Modulation of actomyosin motor function by 1-hexanol
Hideyuki Komatsu1, Taeko Shigeoka, Tetsuo Ohno
1Department of Biochemical Science and Engineering, Kyushu Institute of Technology, Institute of Material Chemistry and Engineering, Kyushu University, Fukuoka, Japan. hide@bse.kyutech.ac.jp
Journal of Muscle Research and Cell Motility
|May 27, 2004
Summary
1-hexanol reversibly alters actomyosin function by activating MgATPase and affecting actin binding states. This perturbation impacts muscle contraction, motility, and tension, suggesting a role in hydrophobic interactions during actomyosin transitions.
Area of Science:
- Biochemistry
- Muscle Physiology
Background:
- Actomyosin ATPase is crucial for muscle contraction.
- Understanding how small molecules affect actomyosin interactions is key to elucidating muscle function.
Purpose of the Study:
- To investigate the effects of 1-hexanol on actomyosin ATPase and related functions.
- To determine the reversibility and concentration-dependent effects of 1-hexanol.
Main Methods:
- Enzyme kinetics assays (K-EDTA-ATPase, MgATPase).
- Spectroscopic methods (tryptophan fluorescence).
- In vitro motility assays and isometric tension measurements in muscle fibers.
Main Results:
- 1-hexanol (0-20 mM) reversibly activated S1 MgATPase.
- It inhibited maximum actin-activated ATPase and reduced actin filament sliding velocity.
- Hexanol altered S1-actin binding affinity and decreased isometric tension.
Conclusions:
- 1-hexanol perturbs actomyosin interactions, particularly affecting the transition to the strong binding state.
- Accelerated Pi release from S1.ADP.Pi suggests a conformational change.
- These perturbations explain the observed inhibition of ATPase activity, motility, and tension.