Question: 11 2 points a draw the structure of the tripeptide...
11. (2 points) a. Draw the structure of the tripeptide Gly-Gly-Ser. b. Draw arrows to the two peptide bonds. c. Now choose one of the peptide bonds and circle all of the atoms that lie in the same plane. d. Next use the other peptide bond and indicate which part can act as a hydrogen-bond donor, and which can act as a hydrogen bond acceptor.
12. (2 points) You find that a particular protein binds to a positively charged chromatography resin at neutral pH, but steadily loses this affinity with decreasing pH. Name two amino acid residues which are likely to be enriched relative to others in this protein. Why does decreasing the pH cause a loss of binding affinity?
13. (1 point) Briefly describe one interesting finding from the prebiotic soup experiments we discussed in Chapter 1.
13. Consider the following peptide:
(2 points) Would this protein be able to form any intermolecular (on the same molecule) disulfide bridges?______
(2 points) Would this protein be able to form any intramolecular (between two molecules) disulfide bridges?______
(2 points) At neutral pH, what will the charge on this peptide be?_______
(2 points) You swallow a solution of this peptide. When exposed to your stomach acid (pH ~1.5 – 2) what is the charge on the peptide
(4 points) You treat the protein with a chemical that acetylates all of the primary amine groups (R-NH2). Does this change the net charge on the protein? ______ If yes, what will the new charge on the peptide be?_________