TABLE 1

Defining the proposed quinidine/KCNQ1 interface by counting contacts between quinidine and KCNQ1 side chains across the 10 best-scoring complexes obtained from docking calculations

This table identifies each KCNQ1 residue with side chain atoms that were within 4Å of quinidine atoms in more than 50% of the 10 best-scoring complexes. Quinidine was docked in the cavity between KCNQ1 subunits A and B (The red volume located between the cyan and green subunits in Fig. 7). A “10” in column 4 means that the residue identified in columns 1–3 was in contact with quinidine in every one of the 10 best-scoring complexes. Note that contacts between quinidine and F351/L251/V254 (bold) are observed in every one of these models. This correlates exactly with our experimental evidence that these three residues are involved with quinidine block and strengthens our hypothesis that the mechanism is an allosteric modulation induced by quinidine binding at this site.