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X-ray structure of a voltage-dependent K+ channel
Youxing Jiang1, Alice Lee, Jiayun Chen
1Howard Hughes Medical Institute, Laboratory of Molecular Neurobiology and Biophysics, Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, Rockefeller University, 1230 York Avenue, New York, New York 10021, USA.
Nature
|May 2, 2003
Summary
We determined the structure of voltage-dependent K+ channels (KvAP) from Aeropyrum pernix. Flexible hinges on voltage-sensor paddles suggest they move to conduct ions across the cell membrane.
Area of Science:
- Structural biology
- Biophysics
- Molecular biology
Background:
- Voltage-dependent K+ channels are crucial for nerve and muscle electrical activity.
- These channels regulate ion conduction based on cell membrane voltage changes.
- Understanding their structure is key to elucidating cellular electrical signaling.
Purpose of the Study:
- To determine the high-resolution crystal structure of the KvAP channel from Aeropyrum pernix.
- To characterize the structural features of the voltage-sensing mechanism in KvAP.
- To provide insights into the gating mechanism of voltage-dependent cation channels.
Main Methods:
- X-ray crystallography was used to determine the structure of the full-length KvAP channel at 3.2 A resolution.
- The isolated voltage-sensor domain was crystallized and resolved to 1.9 A.
- Monoclonal Fab fragments were used to stabilize and crystallize channel complexes.
Main Results:
- The KvAP channel structure reveals a central ion-conduction pore surrounded by unique 'voltage-sensor paddles'.
- These paddles are hydrophobic, cationic, helix-turn-helix structures located on the channel's outer perimeter.
- Flexible hinges were identified connecting the voltage sensors to the pore, indicating potential for movement.
Conclusions:
- The determined structure provides a detailed molecular model of a voltage-dependent K+ channel.
- The 'voltage-sensor paddles' and flexible hinges offer a novel mechanism for voltage-dependent gating.
- This research advances our understanding of ion channel function and cellular electrophysiology.
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