Structural rearrangements underlying ligand-gating in Kir channels.

ABSTRACT: Inward rectifier potassium (Kir) channels are physiologically regulated by a wide range of ligands that all act on a common gate, although structural details of gating are unclear. Here we show, using small molecule fluorescent probes attached to introduced cysteines, the molecular motions associated with gating of KirBac1.1 channels. The accessibility of the probes indicates a major barrier to fluorophore entry to the inner cavity. Changes in fluorescence resonance energy transfer between fluorophores, attached to KirBac1.1 tetramers, show that phosphatidylinositol-4,5-bisphosphate-induced closure involves tilting and rotational motions of secondary structural elements of the cytoplasmic domain that couple ligand binding to a narrowing of the cytoplasmic vestibule. The observed ligand-dep

SUBMITTER: Wang S 

PROVIDER: S-EPMC4277880 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature