Stabilization of α-helix

In the secondary structure of proteins, specifically in the α-helix, the hydrogen bonds form between the carbonyl oxygen atom of one amino acid residue and the amino hydrogen of another residue that is four positions away in the primary sequence. This pattern of hydrogen bonding creates a helical structure that is both stable and common in many proteins. The α-helix is stabilized by these hydrogen bonds, which occur along the backbone of the polypeptide chain, not involving the side chains of the amino acids. This distinction helps differentiate the correct answer from the other options, which either refer to interactions involving side chains, positions that don’t match the pattern seen in α-helices, or α-carbons, which are not directly involved in the hydrogen bonding that stabilizes the α-helix structure. Problem: In protein secondary structure, the α-helix is stabilized by hydrogen bonds. Between which parts of the amino acid residues do these hydrogen bonds form? A) Between the amino group of one residue and the carboxyl group of another residue, four positions away B) Between the side chains of amino acid residues that are three positions apart C) Between the side chain of one residue and the main chain carbonyl of another residue D) Between the α-carbons of adjacent amino acid residues