Voltage sensor ring in a native structure of a membrane-embedded potassium channel.

Area of Science:

• Structural Biology
• Biophysics
• Membrane Protein Research

Background:

• Voltage-gated ion channels are crucial for cellular electrochemical activity and neural information flow.
• Voltage sensor domains detect transmembrane potential, regulating ion flux.
• Previous X-ray structures showed variations in voltage sensor domains, and recent studies indicated lipid influence on channel conformation, leaving the native membrane structure elusive.

Purpose of the Study:

• To elucidate the structural basis of voltage sensing in native membranes.
• To present a detailed view of a voltage-gated potassium channel in its inactivated state within a membrane environment.

Main Methods:

• Electron crystallography of membrane-embedded proteins.
• Biochemical assays.
• Electrophysiological studies.

Main Results:

• A unique conformation, termed the "voltage sensor ring," was observed where four voltage sensor domains surround the pore domain of the KvAP channel.
• This structure differs significantly from known voltage-gated ion channel structures determined in detergents.
• Biochemical and electrophysiological data support the voltage sensor ring as a physiological conformation.

Conclusions:

• Lipids exert substantial influence on voltage-gated potassium channel structure.
• Membrane disruption may alter these lipid-protein interactions.
• The findings have broad implications for understanding lipid-protein interactions and the mechanism of voltage sensing.