Flexibility of the Kir6.2 inward rectifier K(+) channel pore.

ABSTRACT: Interactions of sulfhydryl reagents with introduced cysteines in the pore-forming (Kir6.2) subunits of the K(ATP) channel were examined. 2-Aminoethyl methanethiosulfonate (MTSEA(+)) failed to modify Cd(2+)-insensitive control-Kir6.2 channels, but rapidly and irreversibly modified Kir6.2[L164C] (L164C) channels. Although a single Cd(2+) ion is coordinated by L164C, four MTSEA(+) "hits" can occur, each sequentially reducing the single-channel current. A dimeric fusion of control-Kir6.2 and L164C subunits generates Cd(2+)-insensitive channels, confirming that at least three cysteines are required for coordination, but MTSEA(+) modification of the dimer occurs in two hits. L164C channels were not modified by bromotrimethyl ammoniumbimane (qBBr(+)), even though qBBr(+) caused voltage-dependent

SUBMITTER: Loussouarn G 

PROVIDER: S-EPMC31207 | biostudies-literature | 2001 Mar

REPOSITORIES: biostudies-literature