Question

Answer the following question.

Explain the secondary structure of a protein with examples.

Answer 1

1. There are two types of the secondary structures of protein: α-helix and β-pleated sheets.
2. The polypeptide chain is arranged in a spiral helix. These spiral helices are of two types: α-helix (right-handed) and β-helix (left-handed).
3. This spiral configuration is held together by hydrogen bonds.
4. The sequence of amino acids in the polypeptide chain determines the location of its bend or fold and the position of formation of hydrogen bonds between different portions of the chain or between different chains. Thus, peptide chains form an α-helix structure.
5. Example of α-helix structure is keratin.
6. In some proteins two or more peptide chains are linked together by intermolecular hydrogen bonds. Such structures are called β-pleated sheets.
7. Example of a β-pleated sheet is silk fibres.
8. Due to the formation of hydrogen bonds peptide chains assume a secondary structure.