25-30 August 2019
Henry Ford Building
Europe/Berlin timezone

A single NaK channel conformation is not enough for non-selective ion conduction

Not scheduled
4h
Harnack House and Henry Ford Building

Harnack House and Henry Ford Building

Board: 174
Poster Posters

Speaker

Ms Kitty Hendriks (Leibniz-Forschungsinstitut für Molekulare Pharmakologie)

Description

NaK and other non-selective channels are able to conduct both sodium (Na+) and potassium (K+) with equally high efficiency. In contrast to previous crystallographic results, we show that the selectivity filter (SF) of NaK in native-like lipid membranes adopts two distinct conformations that are stabilized by either Na+ or K+ ions. The atomic differences of these conformations are resolved by solid-state NMR (ssNMR) spectroscopy and molecular dynamics (MD) simulations. Besides the canonical K+ permeation pathway, we identify a side entry ion-conduction pathway for Na+ permeation unique to NaK. Moreover, under otherwise identical conditions ssNMR spectra of the K+ selective NaK mutant (NaK2K) reveal only a single conformational state. Therefore, we propose that structural plasticity within the SF and the selection of these conformations by different ions are key molecular determinants for highly efficient conduction of different ions in non-selective cation channels.

Primary authors

Dr Chaowei Shi (University of Science and Technology of China) Dr Yao He (University of Science and Technology of China) Ms Kitty Hendriks (Leibniz-Forschungsinstitut für Molekulare Pharmakologie) Prof. Bert de Groot (Max Planck Institute for Biophysical Chemistry ) Ms Xiaoying Cai (University of Science and Technology of China) Prof. Changlin Tian (University of Science and Technology of China) Prof. Adam Lange (Leibniz-Forschungsinstitut für Molekulare Pharmakologie) Dr Han Sun (Leibniz-Forschungsinstitut für Molekulare Pharmakologie)

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