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Peroxidative crosslinking of myosins
V Bhoite-Solomon1, G Kessler-Icekson, N Shaklai
1Sackler Institute of Molecular Medicine, Sackler Faculty of Medicine, Tel-Aviv University, Israel.
Abstract:
The effect of myoglobin, free hemin and H2O2 on myosins from heart and skeletal muscle was studied. SDS-gel electrophoresis revealed that each agent caused intermolecular thiol crosslinking of both myosins dissociable by excess of beta-mercaptoethanol. In the simultaneous presence of H2O2 and myoglobin or H2O2 and free hemin, myosin formed covalent aggregates undissociable by beta-mercaptoethanol and therefore assessed to formation of non S-S inter molecular covalent bonds. The latter aggregates are suggested to result from pairing of myosin radicals formed by the H2O2 induced ferryl iron state in myoglobin, free hemin or hemo-myosin.
Insights
Myoglobin, free hemin, and hydrogen peroxide (H2O2) induce crosslinking in heart and skeletal muscle myosins. These agents form non-disulfide covalent bonds, suggesting radical formation and myosin aggregation.
Area of Science:
- Biochemistry
- Muscle Physiology
- Protein Chemistry
Background:
- Myosins are crucial contractile proteins in muscle.
- Oxidative stress can modify protein structure and function.
- The role of myoglobin and hemin in myosin modification is not fully understood.
Purpose of the Study:
- To investigate the effects of myoglobin, free hemin, and hydrogen peroxide (H2O2) on myosins.
- To determine the nature of crosslinking and aggregation induced by these agents.
- To elucidate the underlying mechanisms of myosin modification.
Main Methods:
- SDS-gel electrophoresis was used to analyze myosin.
- Intermolecular thiol crosslinking was assessed.
- The formation of non-S-S covalent bonds was investigated.
Main Results:
- Myoglobin, free hemin, and H2O2 induced intermolecular thiol crosslinking in myosins.
- Non-disulfide covalent aggregates were formed in the presence of H2O2 with myoglobin or free hemin.
- These aggregates were resistant to beta-mercaptoethanol reduction.
Conclusions:
- Myoglobin, free hemin, and H2O2 can cause significant structural modifications to myosins.
- The formation of covalent aggregates suggests a radical-mediated mechanism.
- Understanding these modifications is important for muscle health and disease.