The Shaker K+ Channel S4 Voltage Sensor Translates 10 Å during Gating
| Autor: | Posson, David J., Selvin, Paul R. |
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| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: |
Models
Molecular Patch-Clamp Techniques Protein Conformation Lipid Bilayers Dose-Response Relationship Radiation Models Biological Article Electric Stimulation Membrane Potentials Protein Structure Tertiary Xenopus laevis Oocytes Potassium Shaker Superfamily of Potassium Channels Animals Amino Acid Sequence Ion Channel Gating |
| Popis: | Voltage driven activation of Kv channels results from conformational changes of four voltage sensor domains (VSDs) that surround the K+ selective pore domain. How the VSD helices rearrange during gating is an area of active research. Luminescence Resonance Energy Transfer (LRET) is a powerful spectroscopic ruler uniquely suitable for addressing the conformational trajectory of these helices. Using a new geometric analysis of numerous LRET measurements, we were able for the first time to estimate LRET probe positions relative to existing structural models. The experimental movement of helix S4 does not support a large 15–20 Å transmembrane ‘paddle-type’ movement or a near-zero Å vertical ‘transporter-type’ model. Rather, our measurements demonstrate a moderate S4 displacement of 10 ± 5 Å, with a vertical component of 5 ± 2 Å. The S3 segment moves 2 ± 1 Å in the opposite direction and is therefore not moving as an S3–S4 rigid body. |
| Databáze: | OpenAIRE |
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