In α – helix the bonding occurs between oxygen of carbonyl group of one amino acid and hydrogen of amino group ofans.

In an α-helix structure of proteins, the bonding that occurs is a specific type of dipole-dipole interaction called a hydrogen bond. This bonding happens between the oxygen atom of the carbonyl group (C=O) of one amino acid and the hydrogen atom of the amino group (N-H) of another amino acid.

Here are the steps:

1. The α-helix is a common secondary structure of proteins and is a right-handed coiled strand.

2. The amino acids in an α-helix are arranged in a helical structure, almost like a spiral staircase.

3. Each amino acid is linked to its neighbors by a specific type of bond called a peptide bond, which is a covalent bond formed between the carboxyl group of one amino acid and the amino group of another.

4. In addition to these peptide bonds, there are also hydrogen bonds that form between the oxygen atom of the carbonyl group of one amino acid and the hydrogen atom of the amino group of an amino acid that is four residues earlier in the sequence.

5. This hydrogen bonding pattern is repeated over every fourth amino acid, causing the polypeptide chain to fold into a helix.

6. The hydrogen bonds help to stabilize the α-helix structure, making it a common structural motif in proteins.