BCH 3125 Lecture Notes - Lecture 9: Protein Folding, Pancreatic Ribonuclease, Ribonuclease

• School: University of Ottawa
• Department: Biochemistry
• Course: BCH 3125
• Professor: Corrie Da Costa

Document Summary

This problem set consists of a series of questions relating to lecture 9: Some of these questions are from chapter 5 of. In contrast to ribonuclease, some proteins cannot fold without the assistance of proteins known as molecular chaperones. Two proteins that share more than 50% sequence identity over a 100 residue stretch are likely to have the same three dimensional fold: what level of activity (1, 10, or 100%) is predicted for ribonuclease a when it is subject to each of the following stepwise procedures, i. denatured, then ii. reduced, then iii. exposed to oxygen, then iv. refolded by removing urea, i. denatured, then ii. reduced, then iii. refolded by removing urea while exposed to oxygen i. denatured, then ii. refolded by removing urea. Rationalize the predictions based on the effect of denaturation and reduction oxidation of the ribonuclease a cysteine residues. Assume that all possible unfolded conformations are equally likely and that folding is faster than oxidation.