Protein Structure

There are 4 levels of structure.

Primary for the amino acid sequence, secondary for alpha helices, beta strands and loops.

Tertiary structure is the 3 dimension structure of a folded protein - it consists of 1 polypeptide chain.

Quaternary structure is when multiple subunits join together. A subunit is a single polypeptide chain.


  • Protein structure can explain biological functions
  • Explain disease mechanism
  • Design drugs
  • Understand evolution, as structure is more conserved than sequence.
  • Design new proteins