(A) X-ray structure [PDB ID code 1F0L]. (B) Atomistic model of the partially unfolded T-domain in two different views. The model was obtained from the last MD snapshot of a 6.8 µs MD simulation of the T-domain with all histidines protonated. All histidines are represented in red licorice. Residues K214, P271, P308, D352, and E362 are shown in yellow licorice. Helices TH1, TH2, TH4, TH5, TH8, and TH9 are represented by green, cyan, magenta, orange, blue, and brown ribbons. Other helices are shown in gray ribbons.