Question

Which of the following is the true reason for the alpha helix structure of proteins?

• A. The hydrogen bonds between a carbonyl group of one amino acid and the amino group of another
• B. The hydrogen bonds between variable groups
• C. The interactions between hydrophobic and hydrophilic variable groups
• D. The interactions between the positively and negatively charged variable groups
• E. All of the above

Answer 1

The correct option is A The hydrogen bonds between a carbonyl group of one amino acid and the amino group of another

The alpha helical structure of protein is stabilized by a hydrogen bond, between the hydrogen atom attached to the electronegative nitrogen atom of a peptide linkage and the electronegative carbonyl oxygen atom of the fourth amino acid present on the amino-terminal side of that peptide bond. This makes all peptide bond (except those close to each end of the helix) occupied in such stabilizing hydrogen bonding.
The correct answer is option A.