How many structures do proteins have?

There are four protein structures.
Primary protein structure: Amino acids are located in chains, there is a peptide bond between them.
Secondary protein structure: The ordered amino acids take the form of a spiral. The shape of the helix helps maintain stability of hydrogen bonds.
Tertiary protein structure: Formation of globules due to the formation of ionic, disulfide bonds. The emergence of hydrophobic interactions.
Quaternary protein structure: This structure is characteristic of complex proteins. Formed from two or more globules.