Lodami

I do not really understand the process, but i'll just put my 1's and 2's. Increasing the pH to a value just past the pKa of the carboxylic group would lead to deprotonation of this group. This may help, since the resonance resulting from delocalization of electrons between the carboxylate oxygens can stabilize the carboxylate, reducing the possibility of tautomerization leading to enol formation. So as long as you control your pH U SHOULD BE FINE!!

Well you need to know the protein you are dealing with, the pH and temperature. The 3D structure of the protein is important because you need to be sure that you are substituting an amino acid that contributes to the salt bridge. You need to know the pH because protonation/deprotonation can eliminate formation of a salt bridge by a residue. Temperature is not as important, since most organisms have internal temperatures that range between 28-40 degrees. Finally, if this is an experiment, find a non-polar substitute that resembles the wildtype amino acid in structure. This is to eliminate any effects that might result from structure replacement.