Thermodynamics of Protein Folding Flashcards
Why are electrostatic attractions entropically unfavourable?
Ions are highly solvated in water - so formation localises salt bridge charges.
What is a hydrogen bond and why is it linear?
Formed between a weakly acidic donor group (D-H) and an acceptor bearing a lone pair.
D-H points along acceptor lone pair orbital pi.
What is the hydrophobic effect?
Non-polar substances order surrounding water molecules –> permitting optimisation of H-bonds between water. This causes an unfavourable change in G for hydration so NP substances excluded from aqueous phase to decrease unfavourable energy.
Why do we gain some stability from electrostatic interactions in protein folding?
No enthalpic advantage as charges neutralised by water BUT as water goes free so some entropic favourability.
What relationship exists between hydrophobicity and surface area for non-polar side chains?
Linear relationship. If residues have similar accessible SA - if have a polar gp = ~1kcal less hydrophobic than those with only non-polar.
