Effect of Arachidonic Acid on Myosin II Function

The main contractile proteins in muscle are actin and myosin, the interaction between them is what generates movement and muscle contraction. Muscle myosin, myosin II, is the motor protein that drive muscle contraction through chemo-mechanical coupling; binding adenosine triphosphate (ATP) and hydrolyzing into adenosine diphosphate (ADP) and inorganic phosphate (Pi) as it produces force. This conversion of ATP into ADP and Pi is myosin\u27s ATPase activity. Arachidonic acid is a bioactive lipid and is produced in all eukaryotic cells. It has been shown to stimulate the ATPase activity in smooth muscle myosin II (1). It is postulated to bind to myosin motor domain near the actin-binding site and increase the rate of Pi release, which also increases the ATPase activity of myosin (1). This study will test the effect of arachidonic acid on myosin II from Dictyostelium discoideum, which will specifically test ATPase activity in myosin and myosin\u27s ability to interact with actin. The functional changes in myosin and actin will be tested using the myosin ATPase assay, which measures the rate at which myosin hydrolyses ATP, and actomyosin co-sedimentation assay, to measure the binding interaction and affinity of myosin for actin