In α – helix the bonding occurs between oxygen of carbonyl group of one amino acid and hydrogen of amino group ofans.Second amino acid next to formerFourth amino acid next to formerFifth amino acid next to formerThird amino acid next to former Previous Marked for Review Next

In an α-helix structure of proteins, the bonding occurs between the oxygen of the carbonyl group of one amino acid and the hydrogen of the amino group of the fourth amino acid next to the former. This is a specific type of secondary structure that proteins can form and is stabilized by these hydrogen bonds.

Here are the steps of how this bonding occurs:

1. The α-helix structure begins to form as the polypeptide chain coils around a central axis.

2. The carbonyl (C=O) group of each amino acid is in close proximity to the amino (N-H) group of the amino acid that is fourth down the chain.

3. A hydrogen bond forms between the oxygen of the carbonyl group and the hydrogen of the amino group. This bond is represented as a dotted line in structural models.

4. This pattern of hydrogen bonding repeats along the length of the α-helix, stabilizing its coiled structure.

5. The specific arrangement and bonding of the α-helix structure result in its unique properties, including its strength and flexibility.