Describe the effect on a protein if one or more amino acids are changed.
Cite a specific example.
The effect on a protein if one or more amino acids are changed depends on the specific amino acid(s) involved and their position within the protein sequence. A single amino acid change can result in various consequences, ranging from negligible to severe alterations in protein structure and function.
For instance, a common example is the mutation in the β-globin gene that causes sickle cell anemia. In this case, a specific change occurs in the amino acid sequence of the β-globin protein, where glutamic acid (hydrophilic amino acid) is replaced by valine (hydrophobic amino acid). This single amino acid substitution leads to the formation of abnormal hemoglobin molecules, causing red blood cells to take on a sickle-like shape. These sickled cells do not function properly and can block blood vessels, leading to severe complications in affected individuals.
This example demonstrates how a single amino acid change can result in a significant impact on protein structure, altering its folding, stability, interactions with other molecules, and consequently, its biological function.