Question

Name and thoroughly discuss the 4 non-covalent interactions that are responsible for stabilizing the secondary structures of proteins?

Answer 1

The four non-covalent interactions are-

1. Hydrogen bonds- It involves the carbonyl and amide groups as well as the polar side chains. The formation of alpha helix is because of hydrogen bonding between carboxyl group of first amino acid to amino group of fourth amino acid. Similarly, beta sheets also have hydrogen bonds. Solubility also depends on hydrogen bonding. Proteins with high polar chains can form hydrogen bond in water.

2. Electrostatic interactions- They are formed due to charged nature of amino acids. Ionic bonds or salt bridges are formed in the interior. The specific electric field also regulates the catalytic activity of protein. They affect both thermodynamic and kinetic properties of proteins.

3. Hydrophobic interactions- These are formed between non-polar groups of amino acids. They are important for keeping a protein folded and stable. They allow protein to decrease it's surface area and reduce interactions with the water molecules.

4. Van der waala interactions- They are transient and weak attractive forces of one atom to the other. They are short lived but form important component in protein stabilization. They help the proteins to interact with other molecules. They help in protein-protein recognition.