Publication Date:
1988-12-16
Description:
Site-directed mutagenesis and expression in Xenopus oocytes were used to study acetylcholine receptors in which serine residues (i) were replaced by alanines (alpha, delta subunits) or (ii) replaced a phenylalanine (beta subunit) at a postulated polar site within the M2 transmembrane helix. As the number of serines decreased, there were decreases in the residence time and consequently the equilibrium binding affinity of QX-222, a quaternary ammonium anesthetic derivative thought to bind within the open channel. Receptors with three serine-to-alanine mutations also displayed a selective decrease in outward single-channel currents. Both the direction of this rectification and the voltage dependence of QX-222 blockade suggest that the residues mutated are within the aqueous pore of the receptor and near its cytoplasmic (inner) surface.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Leonard, R J -- Labarca, C G -- Charnet, P -- Davidson, N -- Lester, H A -- NS-11756/NS/NINDS NIH HHS/ -- NS-8083/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1988 Dec 16;242(4885):1578-81.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Biology, California Institute of Technology, Pasadena 91125.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2462281" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Cell Membrane/*physiology
;
Cloning, Molecular
;
Electric Conductivity
;
Female
;
Ion Channels/*physiology
;
Kinetics
;
Membrane Potentials
;
Mutation
;
Oocytes/physiology
;
RNA, Messenger/genetics
;
Receptors, Nicotinic/genetics/*physiology
;
Transcription, Genetic
;
Xenopus
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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