Proteins are found to have two different types of secondary structures viz $\alpha -$ helix and  $\beta -$pleated sheet structure, $\alpha -$helix structure of protein is stabilized by 

Secondary structures of protein denotes the shape in which a long polypeptide chain exists.  The secondary structure exist in two type of structure $\alpha$ -helix and  $\beta$-pleated structure.
In $\alpha$ -helix structure, a polypeptide chain forms all possible hydrogen bonds by twisting into a right handed screw.