A ring of uncharged polar amino acids as a component of channel constriction in the nicotinic acetylcholine receptor

Keiji Imoto, Takashi Konno, Junichi Nakai, Feng Wang, Masayoshi Mishina, Shosaku Numa

Research output: Contribution to journalArticlepeer-review

101 Citations (Scopus)

Abstract

The channel pore of the nicotinic acetylcholine receptor (AChR) has been investigated by analysing single-channel conductances of systematically mutatedTorpedo receptors expressed in Xenopus oocytes. The mutations mainly alter the size and polarity of uncharged polar amino acid residues of the acetylcholine receptor subunits positioned between the cytoplasmic ring and the extracellular ring. From the results obtained, we conclude that a ring of uncharged polar residues comprising threonine 244 of the α-subunit (αT244), βS250, γT253 and δS258 (referred to as the central ring) and the anionic intermediate ring, which are adjacent to each other in the assumed α-helical configuration of the M2-containing transmembrane segment, together form a narrow channel constriction of short length, located close to the cytoplasmic side of the membrane. Our results also suggest that individual subunits, particularly the γ-subunit, are asymmetrically positioned at the channel constriction.

Original languageEnglish
Pages (from-to)193-200
Number of pages8
JournalFEBS Letters
Volume289
Issue number2
DOIs
Publication statusPublished - 1991 Sep 9
Externally publishedYes

Keywords

  • Channel constriction
  • Ionic channel
  • Nicotinic acetylcholine receptor
  • Single-channel recording
  • Site-directed mutagenesis
  • cDNA expression

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

Fingerprint

Dive into the research topics of 'A ring of uncharged polar amino acids as a component of channel constriction in the nicotinic acetylcholine receptor'. Together they form a unique fingerprint.

Cite this