Summary of system parameters and perturbation scenarios.

= 7.4 using pKa values calculated in ref 22. These systems are assumed to be at physiological pH.a Unless otherwise indicated, residues are assigned charge states according to pHIS-p: physiological ionic strength, IS-l: low ionic strength, E31+: residue E31 is protonated, E31A: residue E31 is mutated to A, pH – l: low pH.b Abbreviations: E: Extended, C: Compact;