Question

A typical \( \alpha \)-helix in a native polypeptide chain has

• A. 3.6 amino acid residues per turn
• B. A rise of 5.4 Å per turn
• C. High proline and glycine content
• D. \( \phi \) value of -57° and \( \psi \) value of -47°

Hint:

The \( \alpha \)-helix is characterized by 3.6 residues per turn, a rise of 5.4 Å, and specific backbone angles for stability.

Answer 1

The Correct Option is A, B, D

Step 1: Understanding \( \alpha \)-helix structure.
The \( \alpha \)-helix is a common secondary structure in proteins. It consists of 3.6 amino acid residues per turn, and each turn rises 5.4 Å along the helix. The backbone of the helix has specific values for the phi (\( \phi \)) and psi (\( \psi \)) dihedral angles, typically around -57° and -47°, respectively.
Step 2: Conclusion.
Thus, the correct answer is (D).