A number of studies indicate that proteins fold to limit the solvent accessible surface of non-polar groups. The data below shows how the non-polar amino acid side chains tend to be buried in protein structure. The anomalies in this plot are easily explained. Return to the top. The tertiary structure of proteins is characterized by tightly folded structure with polar groups on the surface and non-polar groups buried.
Structure is determined globally and redundantly.
Return to the top. There are a number of ways to represent the folding of a protein and the arrangement of secondary structure elements within the tertiary structure. While these simplifications don't show the sidechain and mainchain interactions that hold the structures together, they do reveal the folding pattern. Examination of such diagrams reveals recurring structural patterns in protein folding. In this case, alpha helicies are red circles, columns and twists.