Tertiray and Quaternary structure

• Tertiary structure

  Association of the secondary structures into compact domains
• Bonds in tertiary structure

  • Covalent
  • Non-covalent
• Covalent bonds in tertiary structure

  Disulphide bridges formed by Cytosine [-SH]
• Non-covalent bonds in tertiary structure

  • Van Der Waal's
  • Hydrogen
  • Ionic
• Quaternary structure

  Having more than one polypeptide chain within your protein
• Types of quaternary structures

  • Globular
  • Fibrous
• What are globular structures

  Compact domains with active roles in the cell
• What are fibrous structures

  Arranged into fibres and have structural roles
• Structures of fibrous proteins

  • Coiled-coils
  • Beta-sheets
  • Triple helixes
• Fibrous protein examples

  • fibroin
  • collagen
  • Alpha-keratin
• Globular protein examples

  • antibodies
  • haemoglobin
• Describe the structure of Alpha-keratin

  Made of a 7 amino acid repeat, the 2 helixes twist to form a coiled-coil structure
• Describe the structure of Fibroin [silk]

  • 6 amino acid repeat
  • Beta-sheet antiparallel
  • Strong covalent bonds between tertiary structure
  • Beta sheets are held by weak van der waal's forces
• Collagen's primary structure

  • 3 amino acid repeat of glycine, proline and hydroxyproline,
  • 3 collagen peptides wind into a triple helix held by inter-chain hydrogen bonds,
• Antibodies

  Made of 4 polypeptide chains with intra an inter disulphide bridges
• Heamaglobin

  Has 4 polypeptide chains, 2 identical Alpha chains and 2 identical beta chains