Sickle Cell Anemia is a genetic disease.
This means that it results from a damaged gene which then codes for a protein
with a changed amino acid, which then folds incorrectly and has the wrong
shape, and cannot function correctly.
Sickle Cell Anemia is also referred to as a molecular disease, because we understand what is wrong at the level of cells and molecules. The molecule which malfunctions is the b globin chain in hemoglobin (remember that hemoglobin is composed of 4 amino acid chains or polypeptides - 2 a globin chains and 2 b globin chains). The b globin chain is a polypeptide of 146 amino acids. In most people the 6th amino acid is glutamic acid. However in people with sickle cell anemia glutamic acid has been substituted with valine. This change .... of only one amino acid of the 146 .... causes sickle cell anemia, which kills most children who suffer with it by the age of 20 years. |
Go to the CHIME site at the University of Massachusetts.
The rotating model looks like the normal hemoglobin we saw earlier.
However this is a variant of
hemoglobin, which is found in people with sickle cell anemia. Examine
the model carefully noting the hydrophobic patches which are colored white.
After you have examined the model, and read the text:
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