Figure 3.
Ligand-independent gating of Kir6.2ΔC26 334 substituted channels. A total of 13 different substitutions at position 334 gave rise to functional channels. Ligand-independent gating was assessed by measuring open probability PO in the absence of ATP. 10 independent patches were analyzed for each 334 substitution and the average PO is indicated together with the most representative single-channel current record obtained. The current records are listed in descending order of their Ki,ATP. Although the Ki,ATP changed significantly across the mutant channels, the PO remained the same low value measured for the parental wild-type control. This low PO is known to result from dramatically speeded gating from the burst.