Troponin is a wonderful protein that allows for skeletal muscle and cardiac muscle contraction. I don’t know about you but I think that the heart is a pretty important organ. Without this protein, our hearts would not beat and we would die. End of story. But thanks to troponin, our hearts can function as well as our skeletal muscle. Personally being able to move is a pretty great thing. I wouldn’t be able to make peptides and run the NMR if I couldn’t use my hands or eyes. So let’s explore a little bit more about this amazing protein…
First of all troponin is comprised of three subunits of troponin, troponin C, I and T. Calcium activates the troponin complex by binding to a subunit. The binding of calcium induces a conformational change in one subunit. That subunit then causes a conformational change in the second subunit and the second causes a conformational change in the third subunit. Troponin C is the site at which the calcium binds. Troponin I bind to actin and troponin T binds to tropomyosin. Troponin T anchors the protein complex onto the actin. This is a very ordered structure. Only God could have designed something so amazing!
|The top part of the diagram shows the muscle fiber without calcium bound and the bottom part shows the muscle fiber when calcium is bound.|
Lots of studies have been done with troponin and cardiac muscle. Research has shown that levels of troponin in cardiac tissue can be used to determine if patients are at risk of developing coronary artery disease or graft failure when tissue transplant is performed. This is useful information that could make tissue transplants easier. Heart failure results from decreased sensitization of troponin to Ca2+. Research is being done to find sensitizing agents that can increase the sensitivity of troponin to Ca2+ thus stopping heart failure. This would be a great medical advancement. As you can see, troponin has lots of potential in the medical field. And these are just a few of the many reasons that troponin should be the protein of the year!
Labarrere, MD, Carlos A., David R. Nelson, MS, Catherine J. Cox, MD, Douglus Pitts MD, and Philip Kirlin MD. "Cardiac-Specific Troponin I Levels and Risk of Coronary Artery Disease and Graft Failure Following Heart Transplantation." JAMA 284.426 July (2000). Web. 26 Apr. 2011.
Wen-Ji, Dong, Jianli An, Jun Xing, and Herbert Cheung. "Structural transition of the inhibitory region of troponin I within the regulated cardiac thin filament." Arch Biochem Biophys 45615 Dec. (2006): 135-42. Web. 26 Apr. 2011.
Kleerekoper, Qiunn, and John A. Putkey. "Drug Binding to Cardiac Troponin C*." Journal of Biological Chemistry 274.3420 Aug. (1999). Web. 26 Apr. 2011.