Single-particle cryo-EM structure of a voltage-activated potassium channel in lipid nanodiscs

Autor: Doreen Matthies, Chanhyung Bae, Gilman ES Toombes, Tara Fox, Alberto Bartesaghi, Sriram Subramaniam, Kenton Jon Swartz
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: eLife, Vol 7 (2018)
Druh dokumentu: article
ISSN: 2050-084X
DOI: 10.7554/eLife.37558
Popis: Voltage-activated potassium (Kv) channels open to conduct K+ ions in response to membrane depolarization, and subsequently enter non-conducting states through distinct mechanisms of inactivation. X-ray structures of detergent-solubilized Kv channels appear to have captured an open state even though a non-conducting C-type inactivated state would predominate in membranes in the absence of a transmembrane voltage. However, structures for a voltage-activated ion channel in a lipid bilayer environment have not yet been reported. Here we report the structure of the Kv1.2–2.1 paddle chimera channel reconstituted into lipid nanodiscs using single-particle cryo-electron microscopy. At a resolution of ~3 Å for the cytosolic domain and ~4 Å for the transmembrane domain, the structure determined in nanodiscs is similar to the previously determined X-ray structure. Our findings show that large differences in structure between detergent and lipid bilayer environments are unlikely, and enable us to propose possible structural mechanisms for C-type inactivation.
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