- Created by: daisy yemm
- Created on: 21-02-19 14:52
Myosin and actin filaments
Muscle contraction involves myosin and actin filaments sliding over one another -
- Myosin filaments have globular heads that are hinged, so they can move back and forth.
- Each myosin head has a binding site for actin and a binding site for ATP
- Actin filaments have binding sites for myosin heads, called actin-myosin binding sites.
- Another protein called tropomyosin is found between actin filaments. It helps myofilaments move past each other.
Binding sites in resting muscles:
For myosin and actin filaments to slide past each other, the myosin head needs to bind to the actin-myosin binding site on the actin filament.
In a resting muscle, the actin-myosin binding site is blocked by tropomyosin. This means myofilaments can't slide past each other because the myosin heads can't bind to the actin filaments.