Protein structure and synthesis

There are hierarchical degrees of complexity in the formation of a mature, fully-folded protein. Primary structure describes a linear chain of amino acids formed by sequential peptide bonds. Secondary structure consists of backbone interactions in the polypeptide chain that are stabilized by hydrogen bonds between amino acids, forming α-helices and β-pleated sheets.  In tertiary structure, secondary structures come together and further orient themselves depending on hydrophobic interactions, ionic interactions, and disulfide bridges. Finally, quaternary structure consists of multiple tertiary structures coming together to form subunits of a larger protein.