The pore helix dipole has a minor role in inward rectifier channel function.

ABSTRACT: Ion channels lower the energetic barrier for ion passage across cell membranes and enable the generation of bioelectricity. Electrostatic interactions between permeant ions and channel pore helix dipoles have been proposed as a general mechanism for facilitating ion passage. Here, using genetic selections to probe interactions of an exemplar potassium channel blocker, barium, with the inward rectifier Kir2.1, we identify mutants bearing positively charged residues in the potassium channel signature sequence at the pore helix C terminus. We show that these channels are functional, selective, resistant to barium block, and have minimally altered conductance properties. Both the experimental data and model calculations indicate that barium resistance originates from electrostatics. We demonst

SUBMITTER: Chatelain FC 

PROVIDER: S-EPMC3017504 | biostudies-literature | 2005 Sep

REPOSITORIES: biostudies-literature