Figure 6.

Hypothetical pH-induced changes to the putative binding pocket for the PA₆₃ channel and LF. (Left) A top-down view for part of the theoretical model of the PA₆₃ channel²² and the crystal structure of LF⁷⁶ oriented to illustrate the proposed binding site. The colored regions correspond to the subunits shown in the right panel. (Right) A “folded-open” representation of the LF:PA₆₃ channel binding pocket that includes a PA₆₃ dimer and LF. The space-fill region emphasizes the residues at the binding site. The electrostatic potentials were computed at (a) pH 7.2, (b) pH 5.5, and (c) their difference. Negative and positive electrostatic surface potentials are denoted by red and blue, respectively.