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| Cartoon representation - colored by secondary structures |
Many may quickly overlook dystrophin as just another ordinary protein; its importance no greater than the rest. The protein’s structure doesn’t jump off the page like some of the others, there is nothing special or complex about the name, and we’ve never mentioned it in Biochem so of course it can have no significance right? Wrong. Dystrophin actually acts as a vital part of a protein complex that connects the cytoskeleton of a muscle fiber to the surrounding extracellular matrix through the cell membrane. The importance of its bodily function becomes apparent when the protein is lacking. Dystrophin deficiency has been definitively established as one of the root causes of muscular dystrophy; mainly Duchenne muscular dystrophy (DMD). In patients with DMD, the absence of dystrophin leads to the loss of all dystrophin-associated proteins, causing the disruption of the linkage between the subsarcolemmal cytoskeleton and the extracellular matrix. This may render the sarcolemma vulnerable to physical stress. DMD is a severe x-linked recessive form of muscular dystrophy characterized by the rapid progression of muscular degeneration, eventually leading to loss of ambulation and death. It affects 1 in every 4,000 males making it the most prevalent form of muscular dystrophy. It starts with muscle weakness and loss of muscle mass by the age of five starting in the legs and pelvis while working its way up to the arms and neck. Usually by age ten patients are in braces and by twelve confined to a wheelchair. The continual decline eventually leads to paralysis. Life expectancy is in the late teens to early twenties.
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| Surface representation - colored by chains Kinda looks like some sort of monster |
Dystrophin's structure is an antiparallel dimer each comprising two calponin homology domains that are linked by a central alpha helix. Its N-terminal domain binds to F-actin and its C terminus binds to the dystrophin-associated glycoprotein (DAG) complex in the membrane. It is therefore thought to serve as a link from the actin-based cytoskeleton of the muscle cell through the plasma membrane to the extracellular matrix.
References:
Norwood, F. L., A. J. Sutherland-Smith, N. H. Keep, and J. Kendrick-Jones. "The structure of the N-terminal actin-binding domain of human dystrophin and how mutations in this domain may cause Duchenne or Becker muscular dystrophy." Structure 8.481 (2000). Web. 17 Mar. 2011.
Tinsley, J. M., D. J. Blake, M Pearce, A. E. Knight, and J. Kendrick-Jones. "Dystrophin and related proteins." Current Opinion in Genetic Developement 3.3 June (1993): 484-90. Web. 17 Mar. 2011.
Matsumura, K, and KP Campbell. "Dystrophin-glycoprotein complex: its role in the molecular pathogenesis of muscular dystrophies." Muscle Verve 17.1 Jan. (1994): 2-15. Web. 17 Mar. 2011.
Good use of a "story" and I like the second image. Few grammar things: "it's" should be "its" in the first sentence. Perhaps change "the absence of dystrophin leads to the loss in all of the dystrophin-associated proteins," to "...the absence of dystrophin leads to the loss of all dystrophin-associated proteins..." And at the end, you have five spelled out and 10 and 12 in number form. Be consistent. Either make them all numbers or all words. But good job!
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