Helical jackknives control the gates of the double-pore K⁺ uptake system KtrAB.

ABSTRACT: Ion channel gating is essential for cellular homeostasis and is tightly controlled. In some eukaryotic and most bacterial ligand-gated K⁺ channels, RCK domains regulate ion fluxes. Until now, a single regulatory mechanism has been proposed for all RCK-regulated channels, involving signal transduction from the RCK domain to the gating area. Here, we present an inactive ADP-bound structure of KtrAB from Vibrio alginolyticus, determined by cryo-electron microscopy, which, combined with EPR spectroscopy and molecular dynamics simulations, uncovers a novel regulatory mechanism for ligand-induced action at a distance. Exchange of activating ATP to inactivating ADP triggers short helical segments in the K⁺-translocating KtrB dimer to organize into two long helices tha

SUBMITTER: Diskowski M 

PROVIDER: S-EPMC5449183 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature