Thin Filaments (Actin, Troponin, Tropomyosin)
Troponin
Aids in exposure of the binding sites.
Actin
Arranged in 2 single strands that intertwine helically and give them their shape.
Troponin
By itself, cannot move tropomyosin away from the binding site on actin. This process requires calcium ions. After an action potential, calcium ions are released from the terminal cisternae and bind to the ________. This causes a confromational change in the tropomyosin-troponin complex, "dragging" the tropmyosin strands off the binding sites.
Troponin
Calcium attaches here.
Tropomyosin
Entwines around the actin.
Tropomyosin
In the unstimulated muscle, the position of the tropomyosin covers the binding sites on the actin subunits and prevents myosin cross bridge binding.
Troponin
Located at regular intervals on the surface of tropomyosin.
Actin
Looks like a string of pearls, helically twisted.
Tropomyosin
Looks like a vine, covering the bonding site on actin.
Troponin
Looks like an up-side down snowman.
Actin
Protein subunit contains a myosin - binding site.
Actin
The major component of the thin filament.
Tropomyosin
The regulatory protein, tropomyosin is also part of the thin filament.
Tropomyosin
To expose the binding sites for binding with myosin, the ________ molecule must be moved aside.
Tropomyosin-Troponin Complex
Together, tropomyosin and troponin are referred to as the ________.