Secondary structure of a KCNE cytoplasmic domain
Graduate School of Biomedical Sciences; Department of Biochemistry and Molecular Pharmacology
Medical Subject Headings
Amino Acid Sequence; Animals; Cytoplasm; Humans; KCNQ1 Potassium Channel; Mutagenesis, Site-Directed; Patch-Clamp Techniques; Potassium Channels, Voltage-Gated; *Protein Structure, Secondary; Protein Structure, Tertiary; Xenopus laevis
Life Sciences | Medicine and Health Sciences
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.
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Citation: J Gen Physiol. 2006 Dec;128(6):721-9. Link to article on publisher's site
The Journal of general physiology
Rocheleau, Jessica M.; Gage, Steven D.; and Kobertz, William R., "Secondary structure of a KCNE cytoplasmic domain" (2006). GSBS Student Publications. 1016.