The flipping of Phe rings requires that groups surrounding thering move aside momentarily. The rate of ring flipping can bemeasured using NMR. You are studying two mutant versions of aprotein. In both of the mutants, the proteins have considerablesecondary structure, based on circular dichroism studies, and bindthe hydrophobic dye ANS, indicating the formation of thehydrophobic core of the protein. However, in one of the mutants(mutant A), the rate of Phe ring flipping is much higher than inthe other (mutant B). A researcher suggests that one of thesemutants completes the folding process to form a misfolded protein,much like a prion, whereas the other is stuck at some point on thefolding pathway.
A. Which mutant forms a misfolded structure? Explain yourreasoning.
B. Where along the folding pathway is the other mutant stuck?Again, explain your reasoning.