Which of the following statements is incorrect about the secondary structure of protein?

The secondary structure of proteins refers to the shape in which a long polypeptide chain can exist. They are found to exist in two different types of structures, i.e, $\mathrm{\alpha }$-helix and $\mathrm{\beta }$-pleated sheet structure. These structures arise due to the regular folding of the backbone of the polypeptide chain due to hydrogen bonding between 

group of the peptide bond.