Lecture 9

Question 1

Protein Stability

Answer 1

• Electrostatic Forces: Ion-ion interactions
• Van der waals forces between permanent and induced dipoles
• H-bonds
• Hydrophobic forces, most important type of force holding proteins together
• Hydrophobic amino acids tend to be in core
• Charged amino acids tend to be on surface
• Uncharged polar amino acids usually on surface but can be in the interior

Question 2

Protein Denaturation

Answer 2

• Native structure is the biologically relevant 3D structure of a protein
• Denaturation is disrupting the forces holding the native structure together

Question 3

How to denature a protein

Answer 3

• Heat
• addition of organic substances to disrupt hydrophobic interactions
• chaotropic agents, increase the solubility of nonpolar substances in water, disrupt hydrophobic interactions
• Denatured proteins can refold frequently