Electron microscopic analysis of KvAP voltage-dependent K+ channels in an open conformation

Qiu Xing Jiang, Da Neng Wang, Roderick MacKinnon

Research output: Contribution to journalArticle

94 Scopus citations

Abstract

Voltage-dependent ion channels serve as field-effect transistors by opening a gate in response to membrane voltage changes. The gate's response to voltage is mediated by voltage sensors, which are arginine-containing structures that must move with respect to the membrane electric field. We have analysed by electron microscopy a voltage-dependent K+ channel from Aeropyrum pernix (KvAP). Fab fragments were attached to 'voltage sensor paddles' and identified in the electron microscopy map at 10.5 Å resolution. The extracellular surface location of the Fab fragments in the map is consistent with the membrane-depolarized, open conformation of the channel in electrophysiological experiments. Comparison of the map with a crystal structure demonstrates that the voltage sensor paddles are 'up' (that is, near the channel's extracellular surface) and situated at the protein-lipid interface. This finding supports the hypothesis that in response to changes in voltage the sensors move at the protein-lipid interface rather than in a gating pore surrounded by protein.

Original languageEnglish (US)
Pages (from-to)806-810
Number of pages5
JournalNature
Volume430
Issue number7001
DOIs
StatePublished - Aug 12 2004

ASJC Scopus subject areas

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