protein structure

• tertiary structure :

  3D structure formed by further folding of polypeptide

  • disulfide bridges
  • ionic bonds
  • hydrogen bonds
• Primary structure of a protein is the order and number of amino acids in a protein. Initial sequence of amino acids and will determine proteins functions.
• Secondary structures is the shape that the chain of amino acid makes , either alpha helix or beta pleated sheets bonded by weak hydrogen bonds
• Tertiary structure of proteins is the 3D shape of the protein and is formed from further twisting and folding .

  Contains :

  Disulfide bridges

  Ionic bonds

  hydrogen bonds
• Disulfide bridges - strong bonds between sulfur and R group
• Ionic bonds form between the carboxyl group and amino groups that are not in the peptide bond, weaker than disulfide bridges and easily broken by pH
• Hydrogen bonds - numerous and easily broken
• The Quaternary structure of a protein is the precise 3D structure held together by the same types of bond as tertiary structure. May involve addition of prosthetic groups e.g metal ions or phosphate groups