Referenced in: none

Automatically associated channels: Kv1.2 , Kv2.1

Title: Structural dynamics of an isolated voltage-sensor domain in a lipid bilayer.

Authors: Sudha Chakrapani, Luis G Cuello, D Marien Cortes, Eduardo Perozo

Journal, date & volume: Structure, 2008 Mar , 16, 398-409

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/18334215

Abstract
A strong interplay between the voltage-sensor domain (VSD) and the pore domain (PD) underlies voltage-gated channel functions. In a few voltage-sensitive proteins, the VSD has been shown to function without a canonical PD, although its structure and oligomeric state remain unknown. Here, using EPR spectroscopy, we show that the isolated VSD of KvAP can remain monomeric in a reconstituted bilayer and retain a transmembrane conformation. We find that water-filled crevices extending deep into the membrane around S3, a scaffold conducive to transport of protons/cations, are intrinsic to the VSD. Differences in solvent accessibility in comparison to the full-length KvAP allowed us to define an interacting footprint of the PD on the VSD. This interaction is centered around S1 and S2 and suggests a rotation of 70 degrees -100 degrees relative to Kv1.2-Kv2.1 chimera. Sequence-conservation patterns in Kv channels, Hv channels, and voltage-sensitive phosphatases reveal several near-universal features suggesting a common molecular architecture for all VSDs.