Abstract
The X-ray crystallographic structure of KvAP, a voltage-gated bacterial K channel, was recently published. However, the position and the molecular movement of the voltage sensor, S4, are still controversial. For example, in the crystallographic structure, S4 is located far away (>30 Å) from the pore domain, whereas electrostatic experiments have suggested that S4 is located close (<8 Å) to the pore domain in open channels. To test the proposed location and motion of S4 relative to the pore domain, we induced disulphide bonds between pairs of introduced cysteines: one in S4 and one in the pore domain. Several residues in S4 formed a state-dependent disulphide bond with a residue in the pore domain. Our data suggest that S4 is located close to the pore domain in a neighboring subunit. Our data also place constraints on possible models for S4 movement and are not compatible with a recently proposed KvAP model.
Original language | English (US) |
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Pages (from-to) | 741-748 |
Number of pages | 8 |
Journal | Journal of General Physiology |
Volume | 122 |
Issue number | 6 |
DOIs | |
State | Published - Dec 2003 |
Externally published | Yes |
Keywords
- Disulfide
- Helical screw
- S4 movement
- Shaker K channel
- Voltage gated
ASJC Scopus subject areas
- Physiology