Table 3.

pKas of active site glutamates

Residue	E$14{\left[2\right]}^0$	E$14{\left[2\right]}^{-1}$	E$14{\left[1\right]}^0$	E$14{\left[1\right]}^{-1}$
E14[1]	11.38	10.45	n/a	n/a
E14[2]	n/a	n/a	8.80	9.32

The values are computed using PB theory implemented in Adaptive Poisson–Boltzmann Solver (APBS) (23) (see Materials and Methods). For each of the two glutamates, two pKa values are given, which correspond to the protonation state of the other glutamate, as indicated by the residue charge. The SE in the values is ∼1 pKa per unit.