Which of the following types of bonds is primarily responsible for the aberrant aggregation of deoxy HbS molecules resulting from the glutamate to valine mutation in the sixth position of the b-globin chain?
A) amide
B) covalent
C) disulfide
D) hydrophobic
E) ionic

Question

Quizplus · Accepted Answer

The glutamate to valine mutation in sickle cell hemoglobin (HbS) creates a hydrophobic patch on the surface of the hemoglobin molecule, leading to abnormal aggregation through hydrophobic interactions.  HbS is the form of hemoglobin that results due to a missense mutation in the b-globin gene that causes sickle cell anemia. The mutation causing sickle cell anemia is a single nucleotide substitution (A-T) in the codon for amino acid 6. The change converts a glutamic acid codon (GAG) to a valine codon (GTG). Whereas, glutamate is an acidic and hydrophilic amino acid, leucine is hydrophobic. The presentation of this hydrophilic amino acid on the surface of the hemoglobin protein when in the deoxy state allows the proteins to aggregate via hydrophobic interactions. This aggregation leads to deformation of the erythrocyte making it relatively inflexible and unable to traverse the capillary beds.

Which of the Following Types of Bonds Is Primarily Responsible