Week Discussion Questions
1. Label this energy diagram. Label the axis and label the areas of different folding
states.
a. Explain why protein folding is favored entropically.
b. Label a local energy minimum.
c. If a protein gets stuck in a local energy minimum while on its folding pathway,
what can help the protein get out of it?
2. What are four (4) conditions/substances that can denature proteins?
a. How do the Chaotropic agents denature proteins?
3. Draw a 6x histidine tag bound to nickel column.
a. What pH range would this interaction not occur and why?
b. How would you elute the protein from the column?
4. You want to purify a protein using selective precipitation. What three (3) methods
can you use to selectively precipitate your protein? What characteristics would
the protein need for boiling to be appropriate?
5. You are using ammonium sulfate to purify protein Q (pI = 5.0) in a solution at pH
7.0. How should you adjust the pH of the mixture to maximize the amount of
protein Q that precipitates?
6. Which peptide has the greater absorbance at 280 nm and why?
A. Gln-Leu-Glu-Phe-Thr-Leu-Asp-Gly-Tyr
B. Ser-Val-Trp-Asp-Phe-Gly-Tyr-Trp-Ala