Out of the following, which type of interaction is responsible for the stabilisation ofa-helix structure of proteins?

Options

A. Ionic bonding
B. Hydrogen bonding
C. Covalent bonding
D. vander Waals forces

Answer

To determine the type of interaction responsible for the stabilization of the α-helix structure of proteins, we can follow these steps:

### Step 1: Understand the Structure of α-Helix
The α-helix is a common secondary structure found in proteins. It is characterized by a right-handed helical conformation.

### Step 2: Identify the Bonding Interactions
In the α-helix, the backbone of the protein consists of repeating units of amino acids. The key interaction that stabilizes the helical structure is the hydrogen bond.

### Step 3: Analyze the Hydrogen Bonding
In the α-helix, hydrogen bonds form between the carbonyl oxygen (C=O) of one amino acid and the amide hydrogen (N-H) of another amino acid that is four residues earlier in the sequence. This pattern of bonding creates a stable helical structure.

### Step 4: Eliminate Other Options
- **Disulfide Link**: This type of bond involves the oxidation of cysteine residues and is not responsible for the helical structure.
- **Covalent Bond**: While covalent bonds are important in the overall structure of proteins, they do not specifically stabilize the α-helix.
- **Dipole-Induced Dipole**: This interaction is not significant in the stabilization of the α-helix.

### Conclusion
The primary interaction responsible for the stabilization of the α-helix structure of proteins is **hydrogen bonding**.

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