1.  Structures

2. Source: Introduction to Protein Structure by Branden & Tooze Coiled-coil structure- knob in hole

3. Source: Introduction to Protein Structure by Branden & Tooze Coiled-coil structure. Two  helices are interwined and gradually coil around each other. Source: Introduction to Protein Structure by Branden & Tooze

4. Repetitive pattern of amino acids in a coiled- coil  helix.

5. Source: Introduction to Protein Structure by Branden & Tooze Packing of hydrophobic side chains between the two  helices in a coiled-coil structure.

6. Source: Introduction to Protein Structure by Branden & Tooze Salt bridge in a coiled-coil  helix.

7. Source: Introduction to Protein Structure by Branden & Tooze “Knobs in holes” in a coiled-coil  helix.

8. Source: Introduction to Protein Structure by Branden & Tooze Dimeric Rop molecule- “knobs in holes” + “ridges in grooves”

9. Source: Introduction to Protein Structure by Branden & Tooze Globin Domain

10. Source: Introduction to Protein Structure by Branden & Tooze Ridge on groove

11. Source: Introduction to Protein Structure by Branden & Tooze ridges & grooves- surface of side chains of  helix

12. Source: Introduction to Protein Structure by Branden & Tooze Helix packing by “ridges in grooves”

13. Source: Introduction to Protein Structure by Branden & Tooze Sickle-cell hemoglobin

14. Source: Introduction to Protein Structure by Branden & Tooze Hemoglobin molecule

15. Source: Introduction to Protein Structure by Branden & Tooze Sickle-cell hemoglobin molecules polymerization.