Problem 5.18-Copy of this new protein, your research group has made a mutant tha
ID: 984074 • Letter: P
Question
Problem 5.18-Copy of this new protein, your research group has made a mutant that contains two amino acid changes-namely a You have diacovered a novel protein that has a pl 5.5. To study the functional ert ce Phe reside n the normal protein has been replaced by Hs (sido chain pk,61) and a surface Gan has been replaced by Gu(side chain pK, 41) Part A is the pl of the mutant protein predicted to be greater than, less than, or the same as the pl of the normal protein? The pl of the mutant protein predicted to be greater than the pl of the normal protein The pl of the mutant protein predicted to beless than the pl of the normal protein The pl ofthe mutant protein edicted to be the same as the pl of the normal proton. Correct Part B Support your answer with the calculation of an overall charge on the mutant at pH=55. Express your answer using three decimal places. Perform the required calculations on both Glu and His side chains My Answers Give Up Incorrect; Try Again; 5 attempts remainingExplanation / Answer
the pI of the mutant protein will be less than the pI of the normal protein.
pI = 1/2 [pKa 1+Pkb 2} ,pka 1= 6.1,pkb =6.0
= 1/2 [6.1+6.0] =6.15
sp pI of the muatant at ph 5.5 is 6.15 as histidine is weakly basic and polar and glutamate is acidic and polar .so the overall net charge is weakly acidic . so there will be no net charge on the mutant protein.