Ana Fernández-Mariño and Baron Chanda published a paper in Nature Structural & Molecular Biology Volume 25, pages 320–326 (2018).
Their paper, titled “Gating interaction maps reveal a noncanonical electromechanical coupling mode in the Shaker K+ channel” in which they describe a new interaction-energy analysis with which they reveal how movements in the voltage-sensor domains drive movements of the pore domains of voltage-gated ion channels.
They show that the S4 and S5 alpha helices interact through a rack-and-pinion mechanism with a gear ratio of about 4:1.