In: Anatomy and Physiology
Which of the following proteins as a shaft and double
head which binds with ATP and the thin filament
Myosin
Troponin
tropomyosin
Correct Answe is Option A -Myosin
EXPLANATION
Troponin is a protein complex present in the thin filament of muscle contraction.Troponin has 3 main subunit they are Troponin T, Troponin I and troponin C .
Troponin T help to biind the troponin to the tropomyosin
Troponin I help to bind with the Actin filament
Troponin C binds with the calcium which help to displace the Tropomyosin complex from the cative site of the actin.
Tropomyosin is a linear polymer which is seen over the actin filament.
function of tropomyosin is to protect the actin from binding with the myosin until a nerve signal arrives.
Hence option B and C is wrong
Myosin contain a Head, neck , and a tail
Head is double headed which contain Actin binding site and ATP binding site seperately
Neck is the short region in between the Head and tail .
Head and neck together called cross arm
When the calcium released from the sarcoplasmic reticulum bind with the troponin C , the tropomyosin is shited from the active site of the actin .
Myosin head will come and fuse in the active site of the actin and the actin slide over the myosin to produce muscle contraction.
Hence Option A is correct