Proteins are polymers of amino acids which are biomolecules with a central carbon covalently bonded to a carboxyl group, an amino group and an organic R-group.
The R-group determines the properties of an amino acid and classifies them into polar, non-polar, basic and acidic categories.
Proteins possess four types of structural configurations.
The primary structure describes the amino acid acid sequence of the protein. This structure is straight and linear.
The secondary structure involves the formation of alpha helices and beta pleated sheets through hydrogen bonding within or between the primary structure.
Tertiary structure is a more complex form that involves the folding of the amino acid chains through di-sulphide bridges (covalent bonds between sulfur containing side chains) and hydrophobic interactions in which the hydrophobic and non-polar amino acids cluster at the center of the protein and the hydrophilic amino acids arrange at the surface where they interact with water.
Quarternary structure is the most complex form of protein structures. It exists in proteins that possess multiple polypeptide chains or subunits. These are held together by hydrogen bonding or London dispersion forces.
