Table 1. Numbering Scheme for Each System and Its Respective Protonation State.

system	Lysine65	Histidine298 Nδ	Histidine298 Nε
I	protonated	protonated	protonated
II	protonated	protonated	deprotonated
III	protonated	deprotonated	protonated
IV	deprotonated	protonated	protonated
V	deprotonated	protonated	deprotonated
VI	deprotonated	deprotonated	protonated