Valine, a Nonpolar Amino Acid, Shows Up in the Wrong

Multiple Choice

Valine, a nonpolar amino acid, shows up in the wrong place in the hemoglobin of sickle- cell anemia, causing the disease. This is due to a genetic mutation. The result of this mutation is that hemoglobin molecules-which transport oxygen in red blood cells-stick together, causing the red blood cells to become distorted, but without having any significant effect on oxygen binding. Based on what you know about protein structure and the polarity of amino acids, predict where the mutated valine would most likely be found.

A) on the surface of hemoglobin
B) along a nonpolar region of a fi- pleated sheet
C) in the deep interior of hemoglobin
D) in the oxygen binding site of hemoglobin