Supersecondary structures (also called motifs) involves the association of secondary structures in a particular geometric arrangement. If we think of each secondary structure as a 'unit'* (eg. one helix would be one unit and one beta strand would be one unit) then a supersecondary structure would be comprised of at least two 'units' of secondary structure. If we use this definition then a beta sheet could also be considered a supersecondary structure, but for our puposes we have discussed this as a secondary structure. Some of these supersecondary structures are known to have a specific biological, or structural, role but for others their role is unknown. This presentation outlines some supersecondary structures, or structural motifs, seen in proteins.
Helix Superscondary Structures
Sheet Superscondary Structures
Mixed supersecondary Structures
*a 'unit' is also sometimes called an 'element' of secondary structure.