myosin

 myosin   

 

1. A fibrous  protein that forms
2.  contractile filaments of muscle cells
3.  involved in motion in other types of cells.

shape and size 

• Myosin filament is 1.6 μm in length, approximately 300 Å in diameter and has an axial repeat of 429 Å along its length
  

 fumction-  motor protein

1. prototype of a molecular motor
2.  converts chemical energy in the form of ATP to mechanical energy,
3.  contraction of a muscle cell and allow bodies to move or perform an action.
4.  

• In the relaxed state, 
• the muscle fiber is at rest.
• Positively charged sodium ions (Na+) enter the local membrane of the fiber, causing depolarization.
• calcium ions (Ca++) from storage in the sarcoplasmic reticulum (SR) occurs.
• the muscle fiber maintains its original length.
•  

1. contracted state the muscle continues to shorten.

acting- coin spiral different lengh

acting filament 

cont

troponin

complex protein 

cardiac muscle 

skeleton muscle 

troponin 3 type troponin I, troponin T, and troponin C

prevent contraction 

tropomyosin 

1.  prevent mu,scle contracting at the wrong time 
2. 
   

titin

is the biggest protein