Related Experiment Videos
Pore accessibility during C-type inactivation in Shaker K+ channels
C Basso1, P Labarca, E Stefani
1Departmento of Biología, Facultad de Ciencias, Universidad de Chile, Santiago.
FEBS Letters
|July 14, 1998
Summary
Shaker K+ channels undergo C-type inactivation, a process where external barium ions become trapped. This trapping is due to structural changes creating high energy barriers that block ion movement.
Area of Science:
- Molecular biology
- Ion channel biophysics
- Structural biology
Background:
- Shaker K+ channels exhibit two inactivation mechanisms: N-type and C-type.
- C-type inactivation involves structural changes at the channel's external mouth.
Purpose of the Study:
- To investigate pore accessibility during Shaker K+ channel C-type inactivation.
- To use barium ions (Ba2+) as a probe for C-type inactivation.
Main Methods:
- Utilized Ba2+ as a probe to assess pore accessibility.
- Analyzed the interaction between Ba2+ and C-type inactivated Shaker K+ channels.
Main Results:
- External Ba2+ forms a highly stable complex with C-type inactivated Shaker K+ channels.
- Observed "Ba2+ trapping" within the channel during C-type inactivation.
- Identified high energy barriers hindering Ba2+ exit from the channel.
Conclusions:
- C-type inactivation of Shaker K+ channels leads to structural modifications that impede ion permeation.
- The pore environment of C-type inactivated channels significantly restricts Ba2+ movement.
- These findings elucidate the physical basis of ion trapping during channel inactivation.