Structure of the Troponin Complex and Heart Diseases

Cardiovascular disease is the number one cause of death in the United States. Death occurs due to the inability of the heart to distribute blood to the body. This is in turn caused by the inability of the heart of contract. The contraction of the heart is caused by troponin. In this experiment, the researchers were testing the effect that green tea has on the heart and the ability of troponin to bind Ca²⁺. Troponin is a complex made up of two polymers. There is a backbone that is made up of a double helix of actin. On consecutive actin molecules, there is a trimer of troponin C, I and T. Troponin c is the site at which the Ca²⁺ binds. Troponin I is the inhibitory unit of the complex, it serves to regulate the actin-myosin bridge. Troponin T anchors the complex to the filament.  
In this experiment, it was found that drugs that alter the sensitivity of the troponin complex to Ca²⁺ is a safer route than altering the cystolic concentration of Ca²⁺. An increase in sensitivity could increase the amount of Ca that binds to troponin and this causes the heart to contract. Also desensitizers could protect the heart against hypertrophic cardiomyopathy, which is enlargement of the heart. The desensitizers would make the Ca less likely to bind to the troponin and cause an increase in the rate of heart contractions. These sensitizers do not inhibit Ca concentrations, therefore they do not affect homeostasis.

http://www.jbc.org/content/284/34/23012.full