This cholera structure, determined at Argonne's Structural Biology Center, helped scientists understand how the cholera bacterium attacks cells. The cholera structure determined at SBC by Rongguang Zhang is one example of how structure provides important insight. Cholera causes diarrhea that can rob the body of 60 percent of its weight in a single day. It is caused by the bacterium Vibrio Cholerae . This bacterium thrives in the small intestine where it produces a toxin that induces the bowel lining, the epithelium, to secrete massive amounts of water.
Cholera toxin binds to a specific receptor protein on the surface of epithelial cells.
Once bound, the cell swallows the cholera toxin, and its enzyme is released into the cell. Researchers believe the enzyme enters the cell through the inner-tube's center opening. Inside the cell, the toxin turns on the pump to push water into the bowel causing debilitating diarrhea. When researchers saw that the enzyme only pierces the cell but does not destroy it, they understood that healthy cells would naturally replace infected cells after their normal five-day lifespan. In other words, if the victim can survive the diarrhea, he or she can survive the cholera.