Figure 1. Structure of the CHA 16 model.... | Rockefeller University Press

Figure 1.

Structure of the CHA16model. 16 HA models for the concatamers 1234 (WT, left) through 1m2m3m4m (quadruple mutated, right) form, together with the 14 other models of Figs. S2, S3, and S4, the complete CHA16 model. In equilibrium association constants for ligand binding, Kxxxx, x can be 0, 1, and 1 for an empty binding site, a binding site to actually occupy, and a preoccupied binding site, respectively. An HA model has 32 Kxxxxs, either black or red for liganding a WT and mutated subunit, respectively. For the maximum CHA16 model, the total number of black and red Kxxxxs is 64. Blue circles, ligands; white circles, empty binding sites; red crosses, disabled binding sites. The set of closed–open isomerizations on the bottom is valid for all HA models. For the single-, double-, and triple-liganded open channel, the ligands are drawn below the channel cartoon to illustrate that there are 4, 6, and 4 options of occupancy (brackets).

Structure of the CHA ₁₆ model. 16 HA models for the concatamers 1234 (WT, left) through 1m2m3m4m (quadruple mutated, right) form, together with the 14 other models of Figs. S2, S3, and S4, the complete CHA₁₆ model. In equilibrium association constants for ligand binding, Kxxxx, x can be 0, 1, and 1 for an empty binding site, a binding site to actually occupy, and a preoccupied binding site, respectively. An HA model has 32 Kxxxxs, either black or red for liganding a WT and mutated subunit, respectively. For the maximum CHA₁₆ model, the total number of black and red Kxxxxs is 64. Blue circles, ligands; white circles, empty binding sites; red crosses, disabled binding sites. The set of closed–open isomerizations on the bottom is valid for all HA models. For the single-, double-, and triple-liganded open channel, the ligands are drawn below the channel cartoon to illustrate that there are 4, 6, and 4 options of occupancy (brackets).