Referenced in: none

Automatically associated channels: Kv7.1

Title: Serial perturbation of MinK in IKs implies an alpha-helical transmembrane span traversing the channel corpus.

Authors: Haijun Chen, Steve A N Goldstein

Journal, date & volume: Biophys. J., 2007 Oct 1 , 93, 2332-40

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/17545244

Abstract
I(Ks) channels contain four pore-forming KCNQ1 subunits and two accessory MinK subunits. MinK influences surface expression, voltage-dependence of gating, conduction, and pharmacology to yield the attributes characteristic of native channels in heart. The structure and location of the MinK transmembrane domain (TMD) remains a matter of scrutiny. As perturbation of gating analysis has correctly inferred the peripheral location and alpha-helical nature of TMDs in pore-forming subunits, the method is applied here to human MinK. Tryptophan and Asparagine substitution at 23 consecutive sites yields perturbation with alpha-helical periodicity (residues 44-56) followed by an alternating impact pattern (residues 56-63). Arginine substitution across the span suggests that as few as eight sites are occluded from aqueous solution (residues 50-57). We favor a TMD model that is alpha-helical with the external portion of the span at a lipid-protein boundary and the inner portion within the channel corpus in complex interactions.