Publication Date:
1992-03-27
Description:
The high sensitivity of voltage-gated ion channels to changes in membrane potential implies that the process of channel opening is accompanied by large charge movements. Previous estimates of the total charge displacement, q, have been deduced from the voltage dependence of channel activation and have ranged from 4 to 8 elementary charges (e0). A more direct measurement of q in Drosophila melanogaster Shaker 29-4 potassium channels yields a q value of 12.3 e0. A similar q value is obtained from mutated Shaker channels having reduced voltage sensitivity. These results can be explained by a model for channel activation in which the equilibria of voltage-dependent steps are altered in the mutant channels.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schoppa, N E -- McCormack, K -- Tanouye, M A -- Sigworth, F J -- New York, N.Y. -- Science. 1992 Mar 27;255(5052):1712-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/1553560" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
DNA Mutational Analysis
;
Drosophila melanogaster
;
Electric Conductivity
;
In Vitro Techniques
;
*Ion Channel Gating
;
Membrane Potentials
;
Oocytes
;
Potassium Channels/*physiology
;
Structure-Activity Relationship
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
