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- Title
Voltage-dependent caesium blockade of a cation channel from fragmented sarcoplasmic reticulum.
- Authors
Coronado, Roberto; Miller, Christopher
- Abstract
Cs+ ions block the K+ conductance of a voltage-gated ionic channel derived from fragmented sarcoplasmic reticulum (SR) and incorporated into an artificial phospholipid bilayer. The block follows a single-site titration curve with a voltage-dependent dissociation constant of 18 mM at +50 mV. Blockade observed with the macroscopic conductance can be fully accounted for by the reduction of the apparent single-channel conductance in the presence of Cs+. The voltage dependence is explained by assuming that Cs+ binds to the open state of a single channel on a site located about 40% of the way through the membrane from the cis side (the side to which the SR vesicles are added). The blocking site is accessible only from the cis side.
- Publication
Nature, 1979, Vol 280, Issue 5725, p807
- ISSN
0028-0836
- Publication type
Article
- DOI
10.1038/280807a0