Final answer:
The replacement of glutamic acid with valine can drastically alter a protein's structure and function, resulting in conditions like sickle cell anemia due to the misfolding of hemoglobin.
Step-by-step explanation:
The replacement of glutamic acid with valine in a protein would have significant effects on the protein's structure and function, as seen in the example of sickle cell anemia. In this condition, the substitution of hydrophilic glutamic acid by hydrophobic valine in the hemoglobin β-chain leads to a misfolded hemoglobin protein. This change causes red blood cells to assume a sickle shape, disrupting their normal function and leading to severe health consequences. Mutations such as this demonstrate that even a single amino acid change can profoundly affect the three-dimensional structure and resulting activity of a protein, altering its interaction with other molecules and affecting its role in cellular processes.