Referenced in: none

Automatically associated channels: Kv7.1 , Slo1

Title: Secondary structure of a KCNE cytoplasmic domain.

Authors: Jessica M Rocheleau, Steven D Gage, William R Kobertz

Journal, date & volume: J. Gen. Physiol., 2006 Dec , 128, 721-9

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/17130521

Abstract
Type I transmembrane KCNE peptides contain a conserved C-terminal cytoplasmic domain that abuts the transmembrane segment. In KCNE1, this region is required for modulation of KCNQ1 K(+) channels to afford the slowly activating cardiac I(Ks) current. We utilized alanine/leucine scanning to determine whether this region possesses any secondary structure and to identify the KCNE1 residues that face the KCNQ1 channel complex. Helical periodicity analysis of the mutation-induced perturbations in voltage activation and deactivation kinetics of KCNQ1-KCNE1 complexes defined that the KCNE1 C terminus is alpha-helical when split in half at a conserved proline residue. This helical rendering assigns all known long QT mutations in the KCNE1 C-terminal domain as protein facing. The identification of a secondary structure within the KCNE1 C-terminal domain provides a structural scaffold to map protein-protein interactions with the pore-forming KCNQ1 subunit as well as the cytoplasmic regulatory proteins anchored to KCNQ1-KCNE complexes.