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Hinging of rabbit myosin rod
1Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218.
Biochemistry
|December 29, 1987
Summary
Rabbit skeletal muscle myosin rod exhibits hinging within the light meromyosin (LMM)/subfragment 2 (S-2) junction. This conformational change involves a decrease in radius of gyration without altering its helical structure.
Area of Science:
- Biochemistry
- Structural Biology
- Muscle Physiology
Background:
- Myosin rod's structure and function are crucial for muscle contraction.
- Understanding conformational changes in myosin is key to elucidating muscle mechanics.
Purpose of the Study:
- To reexamine the hinging mechanism in rabbit skeletal muscle myosin rod.
- To correlate changes in secondary structure with overall conformation.
Main Methods:
- Elastic light scattering was used to measure the radius of gyration.
- Optical rotation was employed to determine the fraction helix.
- Studies were conducted on myosin rod, light meromyosin (LMM), and long subfragment 2 (long S-2) as a function of temperature.
Main Results:
- Myosin rod's radius of gyration decreased significantly (43 nm to ~35 nm) while fraction helix remained near 100%.
- Light meromyosin (LMM) and long subfragment 2 (long S-2) showed decreased radius of gyration with comparable changes in fraction helix.
- The radius of gyration vs temperature profile of myosin rod was shifted relative to its optical rotation melting curve.
Conclusions:
- The results suggest hinging occurs within the myosin rod, specifically at the LMM/S-2 junction.
- This hinging involves a conformational change independent of alterations in secondary helical structure.
- The findings provide insights into the dynamic properties of myosin rod during muscle function.
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