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Ordered assemblies of myosin minifilaments
Z A Podlubnaya1, D I Levitsky, L A Shuvalova
1Institute of Biological Physics, U.S.S.R. Academy of Sciences, Moscow Region.
Journal of Molecular Biology
|August 5, 1987
Summary
Myosin minifilaments form ordered, periodic structures in solution. ATP causes dissociation, while phosphorylation increases minifilament quantity, impacting myosin studies.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Myosin, a key motor protein, forms minifilaments crucial for muscle contraction.
- Understanding myosin minifilament assembly is vital for comprehending muscle function and related diseases.
Purpose of the Study:
- To investigate the structural organization of myosin minifilaments in vitro.
- To determine the effects of ATP and myosin light chain phosphorylation on minifilament assembly.
Main Methods:
- Electron microscopy was used for negatively stained myosin minifilaments.
- Observations were made in a solution containing citrate buffer (pH 8.0) and MgCl2.
Main Results:
- Myosin minifilaments formed ordered bundles (approx. 330 nm length) with periodic linear and hexagonal structures.
- Myosin heads mediated interactions at the ends of minifilament bundles.
- ATP addition dissociated bundles into individual minifilaments, allowing end-to-end assembly.
- Phosphorylation increased minifilament quantity without altering assembly structure.
Conclusions:
- Myosin minifilament assembly is regulated by ATP and phosphorylation.
- These findings are crucial for myosin-based studies utilizing minifilament systems.